Sphenoid bone (os sphenoidale) occupies a central position at the base of the skull. It participates in the formation of the base of the skull, its lateral sections and a number of cavities and pits. The sphenoid bone consists of a body, pterygoid processes, large and small wings.
The body of the sphenoid bone (corpus sphenoidale) has an irregular shape and six surfaces: upper, lower, posterior, fused (in an adult) with the basilar part of the occipital bone, anterior and two lateral surfaces. On the upper surface of the body there is a depression - the Turkish saddle (sella turcica) with a deep pituitary fossa (fossa hypophysialis). Behind in the Turkish saddle, the back of the saddle (dorsum sellae) is distinguished, and in front - the tubercle of the saddle (tuberculum sellae). On each side, the carotid groove (sulcus caroticus) is visible on the body of the bone - a trace of the fit of the internal carotid artery. On the anterior surface of the body of the sphenoid bone there is a wedge-shaped ridge (crista sphenoidalis). On the sides of the crest are irregularly shaped wedge-shaped shells (conchae sphenoidales), limiting the apertures of the sphenoid sinus. Sphenoid sinus(sinus sphenoidalis) is an air-filled cavity that communicates with the nasal cavity.
The lateral surfaces of the body of the sphenoid bone directly pass into paired small and large wings.
The small wing (ala minor) is a laterally directed flattened bone plate, at the base of which is the optic canal (canalis opticus), leading to the orbit. The posterior free edge serves as the boundary between the anterior and posterior cranial fossae. The anterior edge is connected to the orbital part of the frontal bone and the ethmoid plate of the ethmoid bone. Between the small wing at the top and the upper edge of the large wing is an elongated opening - the upper orbital fissure (fissura orbitalis superior), connecting the cranial cavity with the orbit.
The large wing (ala major) starts from the lateral surface of the body of the sphenoid bone with a wide base and, like the small wing, is directed to the lateral side. It has four surfaces: cerebral, orbital, temporal and maxillary. The concave cerebral surface faces the cranial cavity. It has three holes through which blood vessels and nerves. A round hole (foramen rotundum), located closer to the base of the large wing, leads to the pterygopalatine fossa. At the level of the middle of the wing there is an oval hole (foramen ovale), which opens at the base of the skull, and behind it is a small spinous hole (foramen spinosum). The orbital surface (facies orbitalis) is smooth, participates in the formation of the lateral wall of the orbit. On the temporal surface (facies temporalis) passes the infratemporal ridge (crista infratemporalis), oriented in the anteroposterior direction and delimiting the temporal fossa from the infratemporal fossa on the lateral surface of the skull.
The maxillary surface (facies maxillaris) faces forward - into the pterygo-palatine fossa.
The pterygoid process (processus pterygoideus) is paired, departs downward from the body of the sphenoid bone. As part of the process, the medial and lateral plates (lamina medialis et lamina lateralis) are distinguished. Behind between the plates is the pterygoid fossa (fossa pterygoidea). At the base of the pterygoid process, a narrow pterygoid (vidian) canal (canalis pterygoideus) runs from back to front, connecting the pterygopalatine fossa on the whole skull with the region of the torn foramen.
Occipital bone (os occipitale) is located in the posterior part of the cerebral part of the skull. In this bone, the basilar part, two lateral parts and the occipital scales are distinguished, which surround the large (occipital) foramen (foramen magnum).
The basilar part (pars basilaris) is located in front of the large (occipital) foramen. In front, it connects to the body of the sphenoid bone, together with which it forms a platform - the clivus. On the lower surface of the basilar part there is an elevation - the pharyngeal tubercle (tuberculum pharyngeum), and along the lateral edge there is groove of the inferior petrosal sinus(sulcus sinus petrosi inferioris).
The lateral part (pars lateralis) is steam room, behind it passes into the scales of the occipital bone. Below, on each lateral part, there is an elliptical elevation - the occipital condyle (condylus occipitalis), at the base of which is the hypoglossal nerve canal (canalis nervi hypoglossi). Behind the condyle there is a condylar fossa (fossa condylaris), and at its bottom there is an opening of the condylar canal (canalis condylaris). To the side of the occipital condyle is the jugular notch (incisura jugularis), which, together with the jugular notch of the temporal bone pyramid, forms the jugular foramen. Next to the jugular notch on the cerebral surface is the groove of the sigmoid sinus (sulcus sinus sigmoidei).
Occipital scales (squama occipitalis) - a wide, outwardly convex plate, the edges of which are strongly serrated. On the whole skull, they are connected to the parietal and temporal bones. In the center of the outer surface of the scales, an external occipital protrusion (protuberantia occipitalis externa) is visible, from which a weakly expressed upper convex line (linea nuchae superior) departs on both sides. Down from the protrusion to the large (occipital) foramen passes the external occipital crest (crista occipitalis externa). From its middle to the right and to the left there is a lower line (hinea nuchae inferior). Above the external occipital protrusion, the highest you can sometimes see another line (linea nuchae suprema).
On the inner side of the occipital scales there is a cruciform elevation (eminentia cruciformis), dividing the cerebral surface of the scales into 4 pits. The center of the cruciform eminence forms the internal occipital protuberance (protuberantia occipitalis interna). To the right and to the left of this protrusion is the groove of the transverse sinus (sulcus sinus transversus). Up from the protrusion is the groove of the superior sagittal sinus (sulcus sinus sagittalis superioris), and down to the large (occipital) foramen is the internal occipital crest (crista occipitalis interna).
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1-temporal bone
2 parietal bone
3-coronal (serrated) suture
4 frontal bone
5-frontal tubercle ( tuber frontale)
6-large wing of the sphenoid bone ( ala major ossis sphenoidalis)
7-eye socket
8-lacrimal bone ( os lacrimale)
9-nasal bone ( os nasale)
10-frontal process upper jaw (processus frontalis maxillae)
11-upper jaw
12-alveolar elevations of the upper jaw
13-zygomatic bone
14-chin hole
15-tuberosity of the lower jaw
16-coronal process of the mandible ( processus coronoideus mandibulae)
17-zygomatic arch ( arcus zygomaticus)
18-styloid process ( processus styloideus)
19-articular process of the mandible
20-mastoid process of the temporal bone ( processus mastoideus ossis temporalis)
21-external auditory meatus ( meatus acusticus externus)
22-scales of the temporal bone
23-occipital bone
24-inferior temporal line
25-superior temporal line.
1 frontal bone
2-coronal suture ( sutura coronalis)
3 parietal bone
4-eye socket
5-scales of the temporal bone
6-zygomatic bone
7-upper jaw
8-hole
9-mandible
10-chin puffiness
11 teeth of the lower jaw
12-intermaxillary suture
13-nasal bone ( os nasale)
14-zygomatic arch ( arcus zygomaticus)
15-lacrimal bone ( os lacrimale)
16-large wing of the sphenoid bone ( ala major ossis sphenoidalis)
17-brow ridge
18-glabella (glabella)
19-frontal tubercle.
1-frontal scale ( squama frontalis)
2-frontal tubercle ( tuber frontale)
3-glabella (glabella)
4-zygomatic process ( processus zygomaticus)
5-supraorbital margin ( margo supraorbitalis)
6-nasal part (frontal bone)
7-nasal spine ( spina nasalis)
8 frontal notch
9-brow ridge
10-supraorbital foramen ( foramen supraorbitalis)
11-temporal line
1 parietal edge
2-groove of the superior sagittal sinus ( )
3-frontal crest ( crista frontalis)
4-zygomatic process ( processus zygomaticus)
5-digit impressions ( digital impressions)
6-blind hole ( foramen caecum)
7-bow ( pars nasalis)
8-orbital part ( pars orbitalis)
9-brain elevations
10-arterial grooves ( sulci arteriosi)
11-frontal scales.
1-visual channel ( canalis opticus)
2-back saddle
3-posterior inclined process
4-anterior inclined process
5-small wing ( ala minor)
6-superior orbital fissure ( fissura orbitalis superior)
7-parietal angle
8-large wing (brain surface)
9-round hole ( foramen rotundum)
10-pterygoid canal ( canalis pterygoideus)
11-navicular fossa
12-lateral plate (pterygoid process)
13-wing notch ( incisura pterygoidea)
14-furrow pterygoid hook
15-vaginal process
16 wedge comb
17-body of the sphenoid bone ( corpus ossis sphenoidalis)
18-medial plate (pterygoid process)
19-winged hook ( hamulus pterygoideas)
20-pterygoid fossa ( fossa pterygoidea)
21-groove of the internal carotid artery
1-aperture of the sphenoid sinus ( aperture sinus sphenoidalis)
2-back saddle
3-wedge shell ( conchae sphenoidalis)
4-small wing ( ala minor)
5-superior orbital fissure ( fissura orbitalis superior)
6-cheekbone edge
7-infratemporal surface, 8-awn of the sphenoid bone ( spina ossis sphenoidalis)
9-pterygopalatine sulcus
10-lateral plate ( lamina lateralis)
11-winged hook ( hamulus pterygoideas)
12-medial plate of the pterygoid process
13-vaginal process
14 wedge comb
15-wing notch ( incisura pterygoidea)
16-pterygoid canal ( canalis pterygoideus)
17-round hole ( foramen rotundum)
18-temporal crest ( crista infratemporalis)
19-orbital surface of the greater wing
20-temporal surface of the greater wing
1-groove of the superior sagittal sinus ( sulcus sinus sagittalis superioris)
2-scales of the occipital bone
3-internal occipital protrusion ( )
4-internal occipital crest ( Crista occipitalis inferna)
5-large foramen magnum ( foramen occipital magnum)
6-groove of the sigmoid sinus ( sulcus sinus sigmoidei)
7-muscular channel
8-groove of the inferior petrosal sinus ( )
9-skate ( clivus)
10-basilar (main) part
11-lateral part ( pars lateralis)
12 jugular notch
13 jugular tubercle
14th jugular process
15-inferior occipital fossa
16-groove of the transverse sinus ( sulcus sinus transversi)
17-superior occipital fossa
1-highest protruding line
2-external occipital protrusion ( )
3-top notch line ( linea nachalis superior)
4-lower protruding line ( linea nuchalis inferior)
5-condylar canal ( canalis condylaris)
6-occipital condyle ( condylus occipitalis)
7-intrajugular process
8-pharyngeal tubercle ( tuberculum phanryngeum)
9-basilar (main) part
10-lateral part ( pars lateralis)
11 jugular notch
12 jugular process
13-condylar fossa ( fossa condylaris)
14-large foramen magnum ( foramen occipital magnum)
15-hole surface (platform)
16-external occipital crest ( Crista occipitalis externa)
17-occipital scales
1 frontal angle ( angulus frontalis)
2-superior temporal line
3-frontal edge ( margo frontalis)
4-inferior temporal line
5-wedge angle ( angulus sphenoidalis)
6-scale edge
7-mastoid angle ( angulus mastoideum)
8-occipital margin ( margo occipitalis)
9 parietal tubercle ( tuber parietale)
10-sagittal margin
1-occipital angle ( angulus occipitalis)
2-occipital margin ( margo occipitalis)
3-arterial grooves ( sulci arteriosi)
4-groove of the sigmoid sinus ( sulcus sinus sigmoidei)
5-mastoid angle ( angulus mastoideum)
6-scale edge
7-wedge angle ( angulus sphenoidalis)
8 frontal edge ( margo frontalis)
9 frontal angle ( angulus frontalis)
10-pitted granulations
11-sagittal edge
12-groove of the superior sagittal sinus.
1 cockscomb ( crista galli)
2-orbital plate ( lamina orbitalis)
3-perpendicular plate ( lamina perpendicularis)
4-uncinate process ( processus uncinatus)
5-medium turbinate ( concha nasalis media)
6-superior turbinate ( concha nasalis superior)
7-lattice cells.
1-perpendicular plate ( lamina perpendicularis)
2-medium turbinate ( concha nasalis media)
3 cockscomb ( crista galli)
4-grid cells
5-lattice plate
6-orbital plate ( lamina orbitalis)
7-anterior ethmoid sulcus
8-uncinate process
1-squamous part (scale) of the temporal bone
2-zygomatic process ( processus zygomaticus)
3-articular tubercle ( tuberculum articulare)
4-mandibular fossa ( fossa mandibularis)
5-stony-scaly fissure ( fissure petrosquamosa)
6-stony-tympanic (glazer) fissure
7-styloid process ( processus styloideus)
8-tympanic part of the temporal bone
9-external auditory opening ( porus acusticus externus)
10-mastoid process ( processus mamillaris)
11-mastoid notch ( incisura mastoidea)
12-tympanic mastoid fissure ( fissura tympanomastoidea)
13-supra-anal spine (above the ear canal)
14-mastoid foramen ( foramen mastoideus)
15 parietal notch ( incisura parietalis)
16-temporal line.
1-squamous part of the temporal bone
2-arc elevation ( eminentia arcuata)
3 parietal notch ( incisura parietalis)
4-roof drum cavity
5-groove of the superior petrosal sinus
6-boroed of the sigmoid sinus
7-mastoid foramen ( foramen mastoideus)
8-occipital margin ( margo occipitalis)
9-external opening (aperture) of the vestibule water supply
10-subarc fossa ( fossa subarcuata)
11-sheath of the styloid process ( vagina processus styloidei)
12-styloid process ( processus styloideus)
13-outer opening (aperture) of the cochlear tubule
14-internal auditory opening ( porus acusticus internus)
15-groove of the inferior petrosal sinus ( )
16-posterior surface of the pyramid of the temporal bone
17-top of the pyramid
18-zygomatic process ( processus zygomaticus)
19-arterial grooves
1-external auditory meatus ( meatus acusticus externus)
2-styloid process ( processus styloideus)
3-posture-disarticular tubercle
4-mandibular fossa ( fossa mandibularis)
5-articular tubercle ( tuberculum articulare)
6-zygomatic process ( processus zygomaticus)
7-stony-scaly shell
8-lower process of the pyramid of the temporal bone (roof of the tympanic cavity)
9-stony-tympanic (glazer) fissure
10-musculo-tubal canal ( canalis musculotubarius)
11-internal opening of the carotid canal ( foramen caroticum internum)
12-external opening of the carotid canal ( foramen caroticum externum)
13-stony dimple ( Fossula petrosa)
14-outer opening (aperture) of the cochlear tubule
15-mastoid tubule
16 jugular fossa
17-awl mastoid foramen ( foramen mastoideus)
18-occipital margin ( margo occipitalis)
19-sulcus of the occipital artery ( sulcus arteriae occipitalis)
20-mastoid notch ( incisura mastoidea)
21-mastoid process ( processus mamillaris)
1-scales of the temporal bone
2-mastoid cave ( antrum mastoideum)
3-protrusion of the lateral semicircular canal
4-channel protrusion facial nerve
5-window vestibule
6 probe in the facial nerve canal
7-cleft canal of the greater stony nerve ( hiatus canalis nervi petrosi majoris)
8-cleft canal of the small stony nerve ( hiatus canalis nervi petrosi minoris)
9-groove of the greater stony nerve ( sulcus nervi petrosi majoris)
10-groove of lesser stony nerve ( sulcus nervi petrosi minoris)
11-half-channel of the muscle stretching the tympanic membrane
12-half canal of the auditory tube
13-internal opening of the carotid canal
14-external opening of the carotid canal ( foramen caroticum externum)
15th cape
16-drum cavity
17-pyramidal elevation
18-awl mastoid foramen ( foramen mastoideus)
19-mastoid cells
1 frontal process
2-anterior lacrimal crest
3-infraorbital margin
4-front surface
5-infraorbital foramen
6-nose notch
7-anterior nasal spine
8-body of the upper jaw ( corpus maxillae)
9-alveolar elevations
10-zygomatic process ( processus zygomaticus)
11-alveolar openings
12-hill of the upper jaw ( tuber maxillae)
13-infraorbital furrow
14-orbital surface
1 frontal process
2-tear margin
3-tear groove
4-maxillary (Hymorian) sinus
5-nasal surface of the body of the upper jaw
6-greater palatine sulcus
7-alveolar process
8-palatal process
9 incisor canal ( canalis incisivus)
10-anterior nasal spine
11-shell comb
12-trellised comb.
1 frontal process
2-orbital surface ( facies orbitalis)
3-zygomatic-orbital foramen
4-lateral surface
5-temporal process
1-grid edge
2-left coulter wing
3-free edge
4-palatal edge
1-internasal seam
2-hole of the nasal bone
3-free edge
1 lacrimal process
2-ethmoid process
3-lower (free) edge
1-tear groove
2-posterior lacrimal crest
3 tear hook
1-orbital process
2-trellised comb
3-sphenopalatine notch
4-sphenoid process
5-perpendicular plate (nasal surface)
6-shell comb
7-horizontal plate
8-pyramidal process
9-greater palatine sulcus
10-posterior nasal spine
11-bow comb
12-maxillary process
1-coronary process ( processus coronoideus)
2-condylar process
3-opening of the lower jaw ( foramen mandibulae)
4-cut of the lower jaw ( incisura mandibulae)
5-head of the lower jaw ( caput mandibulae)
6-branch of the lower jaw ( ramus mandibulae)
7 chewy buffer
8-angle of the mandible ( angulus mandibulae)
9-oblique line
10-base of the lower jaw
11-body of the lower jaw ( corpus mandibulae)
12-chin hole
13-chin protrusion
14-alveolar elevations
1-body of the hyoid bone ( corpus ossis hyoidei)
2-big horn
3-small horn
1-palatine process of the upper jaw ( processus palatinus maxillae)
2 incisal hole
3-median palatal suture
4 transverse palatal suture
5-hoana
6-lower orbital fissure ( fissura orbitalis inferior)
7-zygomatic arch ( arcus zygomaticus)
8-wing coulter
9-pterygoid fossa ( fossa pterygoidea)
10-lateral plate of the pterygoid process
11-pterygoid process ( processus pterygoideus)
12-oval hole ( foramen ovale)
13-mandibular fossa
14-styloid process ( processus styloideus)
15-external auditory meatus ( meatus acusticus externus)
16-mastoid process ( processus mamillaris)
17-mastoid notch ( incisura mastoidea)
18-occipital condyle ( condylus occipitalis)
19-condylar fossa ( fossa condylaris)
20-large (occipital) foramen
21-lower protruding line ( linea nuchalis inferior)
22-external occipital protuberance ( protuberantia occipitalis externa)
23-pharyngeal tubercle ( tuberculum phanryngeum)
24-muscle channel
25 jugular hole
26-occipito-stoid seam
27-external carotid foramen
28-awl mastoid foramen ( foramen mastoideus)
29-torn hole
30-stony-tympanic fissure ( fissura petrotympanica)
31-spine hole ( foramen spinosum)
32-articular tubercle ( tuberculum articulare)
33-wedge-scaly seam
34-winged hook ( hamulus pterygoideas)
35-large palatine foramen
36-zygomatic-maxillary suture
1-orbital part of the frontal bone
2-rooster feben
3-lattice plate
4-visual channel ( canalis opticus)
5-pituitary fossa
6-back seat. 7-round hole ( foramen rotundum)
8-oval hole ( foramen ovale)
9-torn hole
10-spine hole ( foramen spinosum)
11-internal auditory opening ( porus acusticus internus)
12 jugular hole
13th sublingual canal
14-lambdoid seam ( sutura lambdoidea)
15-skate ( clivus)
16-beard transverse sinus
17-internal occipital protrusion
18-large (occipital) foramen
19-occipital scales ( squama occipitalis)
20-groove of the sigmoid sinus ( sulcus sinus sigmoidei)
21-pyramid (stony part) of the temporal bone
22-squamous part of the temporal bone
23-large wing of the sphenoid bone ( ala major ossis sphenoidalis)
24-sphenoid wing
1-zygomatic process of the frontal bone ( processus zygomaticus ossis frontalis)
2-large wing of the sphenoid bone (orbital surface)
3-orbital surface of the zygomatic bone
4-frontal process of the zygomatic bone
5-lower orbital fissure ( fissura orbitalis inferior)
6-zygomatic-facial rejection
7-zygomatic bone
8-infraorbital furrow
9-upper jaw (maxillary bone, infraorbital surface)
10-infraorbital foramen
11-orbital surface of the upper jaw ( facies orbitalis maxillae)
12-nasal cavity
13-orbital process of the palatine bone
14-lacrimal bone ( os lacrimale)
15-orbital plate of the ethmoid bone
16-nasal bone ( os nasale)
17-tear groove (lacrimal bone)
18-posterior lacrimal feben (lacrimal bone)
19-frontal process of the upper jaw ( processus frontalis maxillae)
20-front grille hole
21-rear lattice hole
22 frontal notch
23-orbital part (orbital surface) of the frontal bone
24-supraorbital foramen ( foramen supraorbitalis)
25-visual channel ( canalis opticus)
26-minor wing of the sphenoid bone ( ala minor ossis sphenoidalis)
27-superior orbital fissure
1-frontal bone (scales of the frontal bone)
2-frontal sinus
3 cockscomb ( crista galli)
4-ethmoid plate of the ethmoid bone
5-superior turbinate ( concha nasalis superior)
6-medium turbinate ( concha nasalis media)
7-sphenoid sinus ( sinus sphenoidalis)
8-sphenopalatine opening
9-inferior turbinate ( concha nasalis inferior)
10-vertical plate of the palatine bone
11-medial plate of the pterygoid process
12-horizontal plate of the palatine bone
13-palatine process of the maxilla ( processus palatinus maxillae)
14 incisor canal ( canalis incisivus)
15-lower nasal passage ( meatus nasi inferior)
16-middle nasal passage ( meatus nasi medius)
17-upper nasal passage ( meatus nasi superior)
18-nasal bone.
1-coronal suture ( sutura coronalis)
2-sagittal suture ( sutura sagittalis)
3-lambdoid seam ( sutura lambdoidea)
4-occipital bone (scales)
5 parietal bone
6 frontal bone
1 frontal bone
2 frontal crest ( crista frontalis)
3-dimples granulations
4-coronal suture ( sutura coronalis)
5-arterial grooves ( sulci arteriosi)
6 parietal bone
7-groove of the superior sagittal sinus ( sulcus sinus sagittalis superioris)
8-occipital bone
1 frontal seam
2-frontal tubercle ( tuber frontale)
3-anterior (frontal) fontanel
4-coronal suture ( sutura coronalis)
5-parietal tubercle ( tuber parietale)
6-sagittal suture
7-posterior occipital) fontanel
8-occipital bone
9-lambdoid seam
1 frontal bone
2-anterior (frontal) fontanel
3-coronal suture ( sutura coronalis)
4-parietal tubercle ( tuber parietale)
5-posterior (occipital) fontanel
6-occipital bone (scales)
7-mastoid fontanel
8-stony part (pyramid) of the temporal bone
9-scales of the temporal bone
10-tympanic bone (tympanic ring)
11-wedge-shaped (anterolateral) fontanel
12-lower jaw
13-zygomatic bone
14-upper jaw
15-eye socket
1-roof (vault) of the skull
2 frontal bone
3-frontal sinus
4-cell ethmoid bone
5-osseous septum of the nasal cavity
6-anterior nasal spine
7-intermaxillary suture
8-lower jaw
9-chin protrusion
10-nasal cavity
11-maxillary sinus
12-mastoid process ( processus mamillaris)
13-eye socket
Scull, cranium, - consists of two sections - the bones of the skull, ossa cranium, and the bones of the face, ossa faciei.
The skeleton of the head is the skull, cranium, the individual bones of which are subdivided into the bones of the cerebral part of the skull, which form the cranial cavity, cavitas cranii, receptacle for the brain and bones of the face, ossa faciei. The skull serves as a container for the brain (cerebral skull) and some sense organs (organs of vision, hearing and smell).
The bones of the face (the facial part of the skull) make up the skeleton of the face, primary departments digestive and respiratory systems.
Both sections of the skull are formed from separate bones, connected to each other motionlessly with sutures, suturae, and cartilaginous joints, synchondroses, with the exception of the lower jaw, which is movably connected to the skull through the temporomandibular joint, .
The bones of the brain skull, based on data on its development, include unpaired bones: occipital, sphenoid, frontal, ethmoid, vomer - and paired bones: temporal, parietal, inferior nasal concha, lacrimal, nasal.
The bones of the face include paired bones: the upper jaw, palatine bone, zygomatic bone - and unpaired bones: the lower jaw and hyoid bone. The latter, although located in the neck, develops as a bone of the facial part of the skull and is described together with it.
Topographically, the inferior turbinate, vomer, lacrimal, and nasal bones belong to the facial skeleton.
Occipital bone
Occipital bone, os occipitale, unpaired, forms the posterior lower part of the skull. Its outer surface is convex, and the inner, cerebral, concave. In its antero-inferior section there is a large (occipital) foramen, foramen magnum connecting the cranial cavity with the spinal canal. This opening is surrounded by a shallow groove of the occipital sinus, sulcus sinus occipitalis. Based on the data on the development of the occipital bone, four parts are distinguished in it surrounding the large (occipital) foramen: the basilar part is in front of the large (occipital) foramen, the paired lateral parts are on the sides of it and the occipital scales located behind.basilar part, pars basilaris, short, thick, quadrangular; its posterior margin is free, smooth and slightly pointed, limits the large (occipital) foramen anteriorly; the anterior edge is thickened and rough, connects to the body of the sphenoid bone through cartilage, forming a wedge-occipital synchondrosis, Synchondrosis sphenooccipitalis.
In adolescence, cartilage is replaced by bone tissue and both bones merge into one. The upper surface of the basilar part, facing the cranial cavity, is smooth and slightly concave. It makes up a clivus with the part of the body of the sphenoid bone in front of it, clivus directed to the large (occipital) foramen (the medulla oblongata, the bridge and the basilar artery of the brain with branches lie on it). In the middle of the lower, outer, slightly convex surface of the basilar part, there is a small pharyngeal tubercle, tuberculum pharyngeum, (the place of attachment of the anterior longitudinal ligament and the fibrous membrane of the pharynx), and rough lines (traces of attachment of the rectus anterior and long muscles of the head).
The outer, slightly uneven edge of the basilar part and the lateral parts of the occipital bone adjoins the posterior edge of the petrous part of the temporal bone. A petrooccipital fissure is formed between them, fissura petrooccipitalis, on a non-macerated skull, it is made of cartilage, forming petrooccipital synchondrosis, synchondrosis petrooccipitalis, which, as a remnant of the cartilaginous skull, ossifies with age.
lateral parts, paries laterales, somewhat elongated, thickened in the posterior sections, and somewhat narrowed in the anterior; they form the sides of the large (occipital) foramen, growing together in front with the basilar part, and behind with the occipital scales.
On the cerebral surface of the lateral part, at its outer edge, there is a narrow groove of the inferior stony sinus, sulcus sinus petrosi inferioris, which is adjacent to the posterior edge of the stony part of the temporal bone, forming a canal with the same groove of the temporal bone, where the venous inferior stony sinus lies, sinus petrosus inferior.
On the lower, outer, surface of each lateral part is an oblong-oval convex articular process - the occipital condyle, condylus occipitalis. Their articular surfaces converge in front, diverge behind; they articulate with the superior articular fossae of the atlas. Behind the occipital condyle there is a condylar fossa, fossa condylaris, and at the bottom of it is a hole leading to a non-permanent condylar canal, canalis condylaris, which is the site of the condylar emissary vein, v. emissaria condylaris.
On the outer edge of the lateral part there is a large jugular notch with smooth edges, incisura jugularis, on which a small intrajugular process protrudes, processus intrajugularis.
The jugular notch with the same-named fossa of the petrous part of the temporal bone forms the jugular foramen, foramen jugulare.
The intrajugular processes of both bones divide this opening into two parts: a large posterior one, in which the superior bulb of the internal jugular vein lies, bulbus v. jugularis superior, and the smaller anterior through which the cranial nerves pass: glossopharyngeal ( n. glossopharyngeus), wandering ( n. vagus) and additional ( n. accessorius).
Behind and outside, the jugular notch is limited by the jugular process, processus jugularis. On the outer surface of its base there is a small paramastoid process, processus paramastoideus, (place of attachment of the rectus lateral muscle of the head, m. rectus capitis lateralis).
Behind the jugular process, from the side of the inner surface of the skull, there is a wide groove of the sigmoid sinus, sulcus sinus sigmoidei, which is a continuation of the temporal bone groove of the same name. Anteriorly and medially lies a smooth jugular tubercle, tuberculum jugular. Behind and downward from the jugular tubercle, between the jugular process and the occipital condyle, the hyoid canal passes through the thickness of the bone, canalis hypoglossalis, (the hypoglossal nerve lies in it, n. hypoglossus).
occipital scales, squama occipitalis, limits the large (occipital) foramen from behind and makes up most of the occipital bone. This is a wide curved triangular plate with a concave inner (brain) surface and a convex outer one.
The lateral edge of the scales is divided into two sections: a larger upper, strongly serrated lambdoid edge, margo lambdoideus, which, entering into connection with the occipital edge of the parietal bones, forms a lambdoid suture, sutura lambdoidea, and a smaller lower, slightly serrated mastoid margin, margo mastoideus, which, adjacent to the edge of the mastoid process of the temporal bone, forms the occipital-mastoid suture, sutura occipitomastoidea.
In the middle of the outer surface of the scales, in the area of its greatest convexity, there is an external occipital protrusion, protuberantia occipitalis externa easily palpable through the skin. Paired convex upper protruding lines diverge from it to the sides, lineae nuchae superiores, above which and parallel to them there are additional highest protruding lines, lineae nuchae supremae.
From the external occipital protrusion to the large (occipital) foramen, the external occipital crest descends, Crista occipitalis externa. In the middle of the distance between the large (occipital) foramen and the external occipital protrusion from the middle of this crest to the edges of the occipital scales, the lower nuchal lines diverge, lineae nuchae inferiores running parallel to the top. All these lines are the site of muscle attachment. On the surface of the occipital scales below the upper nuchal lines, muscles are attached, ending on the occipital bone.
On the brain surface facies cerebralis, the occipital scales is a cruciform eminence, eminentia cruciformis, in the middle of which rises the internal occipital protrusion ( protuberantia occipitalis interna). On the outer surface of the scales, it corresponds to the outer occipital protrusion.
From the cruciate eminence, the groove of the transverse sinus departs in both directions, sulcus sinus transversi, upward - groove of the superior sagittal sinus, sulcus sinus sagittalis superioris, downward - internal occipital crest, crista occipitalis interna, going to the posterior semicircle of the large (occipital) foramen. To the edges of the furrows and to the internal occipital crest, the dura mater with the venous sinuses lying in it is attached; in the region of the cruciform eminence is the place of confluence of these sinuses.
Sphenoid bone
Sphenoid bone, os sphenoidale, unpaired, forms central department base of the skull.The middle part of the sphenoid bone is the body, corpus, cubic in shape, has six surfaces. On the upper surface, facing the cranial cavity, there is a recess - the Turkish saddle, sella turcica, in the center of which is the pituitary fossa, fossa hypophysialis. It contains the pituitary gland hypophysis. The size of the fossa depends on the size of the pituitary gland. The border of the Turkish saddle in front is the tubercle of the saddle, tuberculum sellae. Behind it, on the lateral surface of the saddle, there is a non-permanent middle inclined process, processus clinoideus medius.
Anterior to the tubercle of the saddle there is a shallow transverse precross groove, Sulcus prechiasmatis. Behind it lies the optic chiasm, chiasma opticum. Laterally, the groove passes into the optic canal, canalis opticus. Ahead of the furrow is a smooth surface - a wedge-shaped elevation, jugum sphenoidale connecting the small wings of the sphenoid bone. The front crane of the upper surface of the body is notched, protrudes slightly forward and connects to the posterior edge of the ethmoid plate of the ethmoid bone, forming a sphenoid-ethmoid suture, sutura spheno-ethmoidalis. The rear border of the Turkish saddle is the back of the saddle, dorsum sellae, which ends on the right and left with a small posterior inclined process, processus clinoideus posterior.
On the sides of the saddle from back to front there is a carotid furrow, sulcus caroticus, (a trace of the internal carotid artery and the accompanying nerve plexus). At the posterior edge of the furrow, on its outer side, a pointed process protrudes - a wedge-shaped tongue, Lingula sphenoidalis.
Back surface the back of the saddle passes into the upper surface of the basilar part of the occipital bone, forming a slope, clivus, (on it lie the bridge, the medulla oblongata, the basilar artery and its branches). The rear surface of the body is rough; through the cartilaginous layer, it connects to the anterior surface of the basilar part of the occipital bone and forms a wedge-occipital synchondrosis, synchondrosis spheno-occipitalis. As we age, cartilage is replaced by bone tissue and both bones fuse together.
The anterior surface of the body and part of the lower face into the nasal cavity. A wedge-shaped ridge protrudes in the middle of the anterior surface, Crista sphenoidalis, its anterior edge is adjacent to the perpendicular plate of the ethmoid bone. The lower process of the crest is pointed, extended downwards and forms a wedge-shaped beak, rostrum sphenoidale. The latter is connected to the opener wings, alae vomeris, forming the vomero-coracoid canal, canalis vomerorostratis lying along the midline between the upper edge of the vomer and the wedge-shaped beak. Lateral to the ridge lie thin curved plates - wedge-shaped shells, conchae sphenoidales. The shells form the anterior and partly inferior walls of the sphenoid sinus, sinus sphenoidalis. Each shell has a small opening - the aperture of the sphenoid sinus, apertura sinus sphenoidalis. Outside of the aperture there are small depressions that cover the cells of the posterior part of the labyrinth of the ethmoid bone. The outer edges of these recesses are partially connected to the orbital plate of the ethmoid bone, forming a sphenoid-ethmoid suture, sutura spheno-ethmoidalis, a lower - with orbital processes, processus orbitalis, palatine bone.
sphenoid sinus, sinus sphenoidalis- a paired cavity, which occupies most of the body of the sphenoid bone; it belongs to the air-bearing paranasal sinuses. The right and left sinuses are separated from one another by the septum of the sphenoid sinuses, septum sinuum sphenoidium, which anteriorly continues into the wedge-shaped ridge. As in the frontal sinuses, the septum is often asymmetrical, as a result of which the size of the sinuses may not be the same. Through the aperture of the sphenoid sinus, each sphenoid sinus communicates with the nasal cavity. The cavity of the sphenoid sinus is lined with a mucous membrane.
small wings, alae minores, sphenoid bone extend in both directions from the anteroposterior corners of the body in the form of two horizontal plates, at the base of which there is a rounded hole. From this hole begins a bone canal up to 5-6 mm long - the visual canal, canalis opticus. It contains optic nerve, n. opticus, and the ophthalmic artery, a. ophthalmica. Small wings have an upper surface facing the cranial cavity, and a lower surface directed into the cavity of the orbit and closing the upper orbital fissure from above, fissura orbitalis superior.
The anterior margin of the lesser wing, thickened and serrated, is connected to the orbital part of the frontal bone. The posterior edge, concave and smooth, protrudes freely into the cranial cavity and is the boundary between the anterior and middle cranial fossae, fossae cranii anterior et media. Medially, the posterior margin ends with a protruding, well-defined anterior inclined process, processus clinoideus anterior, (a part of the dura mater is attached to it - the diaphragm of the Turkish saddle, diaphragma sellae).
Big wings, alae majores, depart from the lateral surfaces of the body of the sphenoid bone and go outward.
The large wing has five surfaces and three edges.
facies cerebralis, concave, turned into the cranial cavity. It forms the anterior part of the middle cranial fossa. Finger-like impressions stand out on it, impressiones digitatae, [gyrorum]), and arterial sulci, sulci arteriosi, (imprints of the relief of the adjacent surface of the brain and middle meningeal arteries).
There are three permanent holes at the base of the wing: a round hole is located inward and anteriorly, foramen rotundum, (through it comes maxillary nerve, n maxillaris), outward and posterior to the round is an oval hole, foramen ovale, (it passes the mandibular nerve, n. mandibularis), and outside and behind the oval - a spinous opening, foramen spinosum, (through it come the middle meningeal artery, vein and nerve). In addition, non-permanent holes occur in this area. One of them is the vein foramen venosum located somewhat posterior to the foramen ovale. It passes the vein going from the cavernous sinus to the pterygoid venous plexus. The second is a rocky hole, foramen petrosum, through which the small stony nerve passes, is located behind the axillary foramen, closer to the axis of the sphenoid bone.
Anteriosuperior orbital surface, facies orbitalis, smooth, rhomboid, facing the cavity of the orbit and forming a large part of its outer wall. The lower edge of the surface is separated from the posterior edge of the orbital surface of the body of the upper jaw - here the lower orbital fissure is formed, fissura orbitalis inferior.
anterior maxillary surface, facies maxillaris, - a triangular area of small length, limited from above by the orbital surface, from the side and below - by the root of the pterygoid process of the sphenoid bone. It is part of the posterior wall of the pterygopalatine fossa, fossa pterygopalatina, it has a round hole.
superior temporal surface, facies temporalis, somewhat concave, takes part in the formation of the wall of the temporal fossa, fossa temporalis, (beams of the temporal muscle begin from it). From below, this surface is limited by the infratemporal crest, crista infratemporali, below the ridge there is a surface on which the oval and spinous openings open. It forms the superior wall of the infratemporal fossa ( fossa infratemporalis), (here begins part of the lateral pterygoid muscle ( m. pterygoideus lateralis).
upper frontal edge, margo frontalis, widely serrated, connects with the orbital part of the frontal bone, forming a wedge-frontal suture, sutura sphenofrontalis. The outer sections of the frontal edge end with a sharp parietal edge, margo parietalis, which with a wedge-shaped angle to the topic of another bone forms a wedge-parietal suture, sutura sphenoparietalis. The internal sections of the frontal margin pass into a thin free margin, which is separated from the lower surface of the lesser wing, limiting the superior orbital fissure from below.
anterior cheekbone, margo zygomaticus, jagged. frontal process, processus frontalis, zygomatic bone and zygomatic edge are connected, forming a sphenoid-zygomatic suture, sutura sphenozygomatica.
posterior scaly edge, margo squamosus, connects to the wedge-shaped edge, margo sphenoidalis, temporal bone and forms a wedge-squamous suture, sutura sphenosquamosa. Posteriorly and outwardly, the scaly edge ends with the spine of the sphenoid bone (the place of attachment of the sphenomandibular ligament, lig sphenomandibularis, and bundles of muscles that strain the palatine curtain, m. tensor veli palatini).
Inward from the spine of the sphenoid bone, the posterior edge of the large wing lies in front of the petrous part, pars petrosa, temporal bone and limits the sphenoid-stony fissure, fissura sphenopetrosa, medially passing into a torn hole, foramen la-lacerum, on a non-macerated skull, this gap is filled with cartilaginous tissue and forms a wedge-stony synchondrosis, synchondrosis sphenopetrosa.
Pterygoid processes ( processus pterygoidei, depart from the junction of the large wings with the body of the sphenoid bone and go down. They are formed by two plates - lateral and medial. lateral plate, lamina lateralis, (processus pterygoidei), wider, thinner and shorter than the medial one (the lateral pterygoid muscle begins from its outer surface, ( m. pterygoideus lateralis). medial plate, lamina medialis, (processus pterygoidei), narrower, thicker and slightly longer than the lateral. Both plates grow together with their front edges and, diverging posteriorly, limit the pterygoid fossa, fossa pterygoidea, (here begins the medial pterygoid muscle, m. pterygoideus medialis). In the lower parts, both plates do not fuse and limit the pterygoid notch, incisura pterygoidea. It contains a pyramidal process processus pyramidalis, palatine bone. The free end of the medial plate ends with a pterygoid hook directed downward and outward, hamulus pterygoideus, on the outer surface of which there is a furrow of the pterygoid hook, sulcus hamuli pterygoidei, (the tendon of the muscle straining the palatine curtain is thrown through it, m. tensor veli palatini).
The posterior superior edge of the medial plate at the base expands and forms a navicular fossa with a wadded shape, fossa scaphoidea.
Outside of the scaphoid fossa is a shallow furrow of the auditory tube, sulcus tubae auditivae, which laterally passes to the lower surface of the posterior edge of the large wing and reaches the spine of the sphenoid bone (the cartilaginous part of the auditory tube is adjacent to this groove). Above the navicular fossa and medially there is an opening with which the pterygoid canal begins, canalis pterygoideus, (vessels and nerves pass through it). The canal runs in the sagittal direction in the thickness of the base of the pterygoid process and opens on the maxillary surface of the greater wing, on the posterior wall of the pterygopalatine fossa.
The medial plate at its base passes into an inwardly directed flat, horizontally running vaginal process, processus vaginalis, which is located under the body of the sphenoid bone, covering the side of the vomer wing, ala vomeris. At the same time, the groove of the vaginal process facing the wing of the vomer is the vomerovaginal groove, sulcus vomerovaginalis, turns into the vomerovaginal canal, canalis vomerovaginalis.
Outward from the process there is a sagittally running small palatovaginal groove, Sulcus palatovaginalis. The sphenoid process of the palatine bone adjacent from below, processus sphenoidalis ossis palatini, closes the furrow into the canal of the same name, canalis palatovaginalis, (in the vomerovaginal and palatine-vaginal canals, the nerve branches of the pterygopalatine ganglion pass, and in the palatine-vaginal canal, in addition, the branches of the sphenoid-palatine artery).
Sometimes the pterygoid process is directed from the posterior edge of the outer plate towards the spine of the sphenoid bone, processus pterygospinosus, which can reach the specified awn and form a hole.
The anterior surface of the pterygoid process is connected to the posterior surface of the upper jaw in the region of the medial edge of the tubercle, forming the sphenoid-maxillary suture, sutura sphenomaxillaris, which lies deep in the pterygopalatine fossa.
frontal bone
frontal bone, os frontale, in an adult forms the anterior part of the cranial vault and partly its base. It consists of four parts: the frontal scale, two orbital parts and the nasal part.frontal scales
frontal scales, squama frontalis, convex anteriorly, has the following surfaces: external, or frontal, two temporal, or lateral, and internal, or cerebral.
Outside surface, facies externa, smooth, convex anteriorly. Elevation is not always noticeable along the midline - a metopic suture, sutura metopica) - a trace of fusion of the halves of the frontal bone that were present in early childhood. In the anterior sections, the frontal surface of the scales passes into the orbital surface, facies orbitalis, forming on each side the supraorbital margin, margo supraorbitalis, which is the upper part of the orbital margin, margo orbitalis. Above and parallel to the supraorbital margin, an arcuate eminence protrudes more or less prominently - the superciliary arch, arcus superciliaris. Above each superciliary arch, a rounded elevation is visible - the frontal tubercle, tuber frontale. Between the bulges of the superciliary arches and slightly above them, the surface of the frontal scales in the region of the glabella looks like a somewhat in-depth area - this is a glabella, glabella. The inner third of the supraorbital margin has a small supraorbital notch, incisura supraorbitalis. This notch is highly variable and can be expressed in the form of a supraorbital foramen, foramen supraorbital. Closer to the median line, i.e. more medially, lies a no less pronounced frontal notch, incisura frontalis, (in the supraorbital notch, the lateral branch of the supraorbital nerve and vessels pass, in the frontal - the medial branch of the same nerve and vessels). At the site of this notch, a frontal opening may form, foramen frontale.
Laterally, the supraorbital margin passes into a blunt, triangular-shaped zygomatic process, processus zygomaticus, its serrated edge connects with the frontal process of the zygomatic bone, forming the fronto-zygomatic suture, sutura frontozygomatica.
From the zygomatic process, the temporal line is directed upward and backward in an arcuate manner, linea temporalis, it separates the frontal surface of the scale from the temporal surface. temporal surface, facies temporalis, is the anterior superior part of the temporal fossa, fossa temporalis, where the anterior bundles of the temporalis muscle begin.
Inner surface, facies interna, concave. It has slightly pronounced finger-like impressions ( impressiones digitatae, and non-permanent arterial sulci, sulci arteriosi, (as an impression of the relief of the brain and blood vessels adjacent here).
In the middle of the inner surface of the frontal scales there is a groove of the superior sagittal sinus, sulcus sinus sagittalis superioris. Its both edges, heading up and backwards, pass into the parietal bone groove of the same name, and below they connect into a sharp frontal crest, crista frontalis, (a process of the dura mater is attached to it - the crescent of the brain). The lowest part of the crest and wing of the ethmoid cockscomb, ala cristae galli ossis ethmoidalis, form a channel - a blind hole, foramen cecum, which contains a vein that drains blood from the nasal cavity to the superior sagittal sinus.
The upper, or posterior, edge of the frontal scales is the parietal edge, margo parietalis, thickened; its jagged edge connects to the frontal edge of the parietal bones, forming a coronal suture, sutura coronalis. The lower sections of the scales are triangular in shape, connected to the frontal edge of the large wings of the sphenoid bone.
Each eye part pars orbitalis, the frontal bone is part of the upper wall of the orbit. From the supraorbital edge of the frontal scale, it is directed backward and horizontally. It distinguishes between the lower orbital and upper cerebral surfaces.
eye surface, facies orbitalis, facing the cavity of the orbit, smooth and concave. In the lateral part of it, at the base of the zygomatic process, lies a shallow fossa of the lacrimal gland, fossa glandulae lacrimalis, is the location of the lacrimal gland.
In the medial part of the orbital surface there is a weakly expressed trochlear fossa, fovea trochlearis, near which there is often a cartilaginous trochlear spine, spina trochlearis, (a cartilaginous ring is attached here, which is a block of the tendon of the superior oblique muscle of the eyeball).
superior cerebral surface, facies cerebratis, the orbital part has well-defined imprints of the adjacent surface of the frontal lobes of the brain in the form of finger-like impressions, impressiones digitatae, gyrorum).
Orbital parts
The orbital parts are separated from each other by a lattice notch, incisura ethmoidalis, in which the lattice plate is located, lamina cribrosa, ethmoid bone. The notch is bounded on the sides by an edge, outside of which dimples lie, covering the cells of the upper part of the ethmoid labyrinth that are open upwards, forming their upper wall. Between the ethmoid dimples, two grooves pass in the transverse direction - anterior and posterior, which, together with the same grooves of the labyrinth of the ethmoid bone, form tubules. The latter open on the inner wall of the orbit - which are two small openings: the anterior ethmoid opening, foramen ethmoidale anterius, (the anterior ethmoid vessels and nerve pass through it), and the posterior ethmoid opening, foramen ethmoidale posterius, (posterior ethmoidal vessels and nerve pass through it). The edge of the cribriform notch connects to the upper edge of the orbital plate, lamina orbitalis, ethmoid bone, forming a fronto-ethmoid suture, sutura frontoethmoidalis, and in front - with the lacrimal bone - the frontal-lacrimal suture, sutura frontolacrimalis.
The posterior edge of the orbital part, racey and serrated, connects to the lesser wing of the sphenoid bone, forming the inner section of the sphenoid-frontal suture, sutura sphenofrontalis.
The lateral margin of the orbital part is rough, triangular in shape. It connects to the frontal edge of the large wing of the sphenoid bone and forms the outer section of the sphenoid-frontal suture.
bow
bow part, pars nasalis, frontal bone in the form of an arc closes the ethmoid notch in front. Ahead, in the middle of the nasal part, the nasal spine (sometimes double) protrudes obliquely downwards and forwards ( spina nasalis, pointed at the end and flattened laterally. It is surrounded in front and side by a jagged nasal edge, margo nasalis. It connects to the upper edge of the nasal bone, forming the fronto-nasal suture, sutura frontonasalis, and with the frontal process ( processus frontalis) of the upper jaw, forming a frontal-maxillary suture, sutura frontomaxillaris. The lower surface of the posterior sections of the nasal part has shallow dimples, which, as noted, cover the cells of the labyrinths of the ethmoid bone that are open upwards.
On each side of the nasal spine there is one aperture of the frontal sinus, apertura sinus frontalis; heading up and anteriorly, it leads into the cavity of the corresponding frontal sinus.
frontal sinus, sinus frontalis, - a paired cavity lying between both plates of the frontal bone in its anteroinferior sections. The frontal sinus is attributed to the air-bearing bones of the sinuses. The right sinus is separated from the left by the vertical septum of the frontal sinuses, septum sinuum frontalium. Deviating to the side, the septum causes an unequal size of the cavities of both sinuses. The boundaries vary drastically. Sometimes the frontal sinuses reach up to the frontal tubercles, down to the supraorbital margins, posteriorly to the lesser wings of the sphenoid bone, and laterally to the zygomatic processes. The aperture of the frontal sinus connects the frontal sinus and the middle nasal passage, meatus nasi medius, nasal cavity. The cavity of the sinuses is lined with a mucous membrane.
Ethmoid bone
Ethmoid bone, os ethmoidale, unpaired. Most of it lies in the upper parts of the nasal cavity, the smaller part - in the anterior parts of the base of the skull. It has the shape of an irregular cube, consists of air cells and belongs to the group of air bones, ossa pneumatica.In the ethmoid bone, there is a ethmoid plate running horizontally, a perpendicular plate lying vertically, and ethmoid labyrinths located on both sides of the latter.
lattice plate, lamina cribrosa, is the upper wall of the nasal cavity, is located horizontally in the ethmoid notch of the frontal bone, forming a fronto-ethmoid suture, sutura frontoethmoidalis. It is perforated with 30-40 small holes, foramina fibrosae through which the nerves (fibers of the olfactory nerves) and blood vessels pass.
perpendicular plate, lamina perpendicularis, is divided into two parts: a smaller upper one, lying above the cribriform plate, and a larger lower one, located under this plate. The upper part forms a cockscomb, crista galli, and is directed into the cranial cavity (a crescent of the brain is attached to the crest - a process of the dura mater).
The border of the anteroinferior edge of the cockscomb on each side is a non-permanent formation - the wing of the cockscomb, ala cristae galli. Both processes delimit behind and above the blind opening, foramen cecum, frontal bone. The lower part of the perpendicular plate of an irregular quadrangular shape is directed vertically down into the nasal cavity, and forms the anterior upper part of the bony septum. From above, it adjoins the nasal spine of the frontal bone, in front - to the nasal bones, behind - to the wedge-shaped crest, from below - to the vomer, and in front and below - to the cartilaginous part of the nasal septum. Often there is a deviation of all or part of the perpendicular plate to the side.
grid maze, labyrinthus ethmoidalis, - a paired formation, located on both sides of the perpendicular plate, adjacent to the lower surface of the cribriform plate. Consists of numerous air-carrying lattice cells, cellulae ethmoidales, communicating both with each other and through a series of holes with the nasal cavity. The ethmoid cells are lined with mucous membrane, which is a direct continuation of the nasal mucosa.
The cells located in front open into the middle nasal passage, the middle and posterior ones communicate with the upper nasal passage.
The lateral wall is a thin smooth orbital plate, lamina orbitalis, which forms most of the inner wall of the orbit. The plate is connected at the top with the frontal bone, forming a fronto-ethmoid suture, sutura fronto-ethmoidalis, below - with the upper jaw - ethmoid-maxillary suture, sutura ethmoidomaxillaris, and with the orbital process of the palatine bone - palatine-ethmoid suture, sutura palate-ethmoidalis, in front - with the lacrimal bone - lacrimal-ethmoid suture and behind - with the sphenoid bone - sphenoid-ethmoid suture, sutura spheno-ethmoidalis. Two small grooves run along the upper edge of the labyrinth - the anterior and posterior ethmoid grooves, which, with the same grooves of the frontal bone, form tubules that open with the anterior and posterior ethmoid openings, foramina ethmoidales anterius and posterius, (vessels and nerves of the same name pass through these openings).
The medial wall of the labyrinth is a rough, grooved plate that forms most of the lateral wall of the nasal cavity. On its surface, facing the perpendicular plate, there are two thin, slightly curved along the edges and wrapped outward processes: the upper one is the superior nasal concha, concha nasalis superior, and the lower one is the middle nasal concha, concha nasalis media. Sometimes above the superior nasal concha there is a rudimentary process in the form of a thin bone comb - the highest nasal concha, concha nasalis suprema. In the upper-posterior section of the medial wall of the labyrinth, between the upper and middle nasal conchas, a slit-like space is formed - the upper nasal passage, meatus nasi superior. The gap under the middle nasal concha is the middle nasal passage, meatus nasi medius.
From the lower anterior surface of each labyrinth, anteriorly and downwards from the middle nasal concha, a hook-shaped process curved backwards and downwards departs, processus uncinatus. On the whole skull, it connects with the ethmoid process, processus ethmoidalis, inferior turbinate.
Behind and above the uncinate process is one of the largest cells, which has the form of a swelling - a ethmoid vesicle, bulla ethmoidalis.
Between the uncinate process below and in front and the large ethmoid vesicle behind and above there is a gap - a ethmoid funnel, infundibulum ethmoidale, the upper end of which communicates with the opening of the sinus of the frontal bone. The posterior edge of the uncinate process and the lower surface of the large cribriform vesicle form a semilunar fissure, hiatus semilunaris through which the maxillary sinus communicates with the middle nasal passage.
Coulter
coulter, vomer, is an unpaired plate elongated in the form of a rhombus, forming the posterior part of the nasal septum.The vomer, excluding its posterior edge, is usually somewhat curved to the side,
The upper edge of the coulter is thicker than the others. It is separated by the furrow of the coulter, sulcus vomeris, into two processes bent outward - the wings of the vomer, alae vomeris. They are adjacent to the lower surface of the body of the sphenoid bone and cover its beak, forming a sphenoid vomer suture, sutura sphenomeriana. Such seams will sag to the schindile, schyndilesis. This section is the wedge-shaped part of the coulter, pars cuneiformis vomeris.
The posterior edge of the bone is the choanal crest, crista choanalis vomeris, slightly pointed, separates the posterior openings of the nasal cavity - choanae, choanae.
The anterior and lower margins are rough. The lower edge is connected to the nasal crest of the upper jaw and palatine bone, and the anterior (beveled) - at the top with the perpendicular plate of the ethmoid bone, at the bottom - with the cartilage of the nasal septum.
Temporal bone
Temporal bone, os temporale, steam room, participates in the formation of the base of the skull and the lateral wall of its arch. It contains the organ of hearing and balance. It articulates with the lower jaw and is the support of the chewing apparatus.On the outer surface of the bone there is an external auditory opening, porus acusticus externus, around which there are three parts of the temporal bone; above - the scaly part, inside and behind - the stony part, or pyramid, in front and below - the drum part.
The squamous part of the temporal bone
scaly part, pars squamosa, has the shape of a plate and is located almost in the sagittal direction. outer temporal surface, facies temporalis, the scaly part is slightly rough and slightly convex. In the posterior part of it, the groove of the middle temporal artery passes in the vertical direction, sulcus arteriae temporalis mediae
In the posterior inferior part of the squamous part, an arcuate line passes, which continues into the lower temporal line, linea temporalis inferior, parietal bone.
From the scaly part, above and somewhat anterior to the external auditory opening, the zygomatic process extends in the horizontal direction, processus zygomaticus. It is, as it were, a continuation of the supramastoid crest, crista supramastoidea located horizontally along the lower edge of the outer surface of the scaly part. Beginning with a broad root, the zygomatic process then narrows. It has an inner and outer surface and two edges - a longer upper and lower, shorter. The anterior end of the zygomatic process is serrated. The zygomatic process of the temporal bone and the temporal process, processus temporalis, the zygomatic bone are connected using the temporo-zygomatic suture, sutura temporozygomatica, forming the zygomatic arch, arcus zygomaticus.
On the lower surface of the root of the zygomatic process is a transversely oval-shaped mandibular fossa, fossa mandibularis. The anterior half of the fossa, up to the stony-squamous fissure, is the articular surface, facies articularis, temporomandibular joint. Anteriorly, the mandibular fossa limits the articular tubercle, tuberculum articulare.
The outer surface of the squamous part is involved in the formation of the temporal fossa, fossa temporalis, (here the bundles of the temporal muscle begin, m. temporalis).
Inner cerebral surface facies cerebralis, slightly concave. It has finger-like indentations, impressiones digitatae, as well as the arterial sulcus, sulcus arteriosus, (it contains the middle meningeal artery, a. meningea media).
The squamous part of the temporal bone has two free edges - sphenoid and parietal.
Antero-inferior wedge-shaped edge, margo sphenoidalis, wide, serrated, connects to the scaly edge of the large wing of the sphenoid bone and forms a wedge-scaly suture, sutura sphenosquamosa. superior posterior parietal margin, margo parietalis, pointed, longer than the previous one, connected to the scaly edge of the parietal bone.
Pyramid of the temporal bone
Pyramid, rocky part - pars petrosa, the temporal bone consists of posterolateral and anteromedial sections.
The posterolateral part of the petrous part of the temporal bone is the mastoid process, processus mastoideus, which is located posterior to the external auditory opening. It distinguishes between the outer and inner surfaces. The outer surface is convex, rough and is the site of muscle attachment. From top to bottom, the mastoid process passes into a cone-shaped protrusion, which is well palpable through the skin,
On the inside, the process is limited by a deep mastoid notch, incisura mastoidea, (the posterior belly of the digastric muscle originates from it, venter posterior m. digastrici). Parallel to the notch and somewhat posteriorly is the sulcus of the occipital artery, sulcus arteriae occipitalis, (trace of the adjacent artery of the same name).
On the inner, cerebral, surface of the mastoid process, there is a wide S-shaped groove of the sigmoid sinus, sulcus sinus sigmoidei, passing at the top into the sulcus of the parietal bone of the same name and further into the sulcus of the transverse sinus of the occipital bone (the venous sinus lies in it, sinus transversa). From top to bottom, the sulcus of the sigmoid sinus continues as the sulcus of the occipital bone of the same name.
Behind the border of the mastoid process is a jagged occipital margin, margo occipitalis, which, connecting with the mastoid edge of the occipital bone, forms the occipital-mastoid suture, sutura occipitomastoidea. In the middle of the length of the seam or in the occipital margin is the mastoid opening, foramen mastoideum, (sometimes there are several), which is the location of the mastoid veins, vv. emissariae mastoidea connecting the saphenous veins of the head with the sigmoid venous sinus, as well as the mastoid branch of the occipital artery, ramus mastoideus a. occipitalis.
From above, the mastoid process is bounded by the parietal edge, which, on the border with the same edge of the squamous part of the temporal bone, forms a parietal notch, incisura parietalis; it includes the mastoid angle of the parietal bone, forming the parieto-mastoid suture, sutura parietomastoidea.
At the point of transition of the outer surface of the mastoid process into the outer surface of the squamous part, one can notice the remains of the squamous-mastoid suture, sutura squamosomastoidea, which is well expressed on the skull of children.
On the cut of the mastoid process, the bone air-bearing cavities located inside it are visible - mastoid cells, cellulae mastoideae. These cells separate the bony mastoid walls from one another ( paries mastoideus). The permanent cavity is the mastoid cave, antrum mastoideum, in the central part of the process; mastoid cells open into it, it connects to the tympanic cavity, cavitas tympanica. The mastoid cells and the mastoid cave are lined with a mucous membrane.
The anteromedial part of the petrous part lies medially from the squamous part and the mastoid process. It has the shape of a trihedral pyramid, the long axis of which is directed from the outside and back to front and medially. The base of the stony part is turned outwards and backwards; top of the pyramid apex partis petrosae, directed inward and anteriorly.
In the stony part, three surfaces are distinguished: anterior, posterior and lower, and three edges: upper, posterior and anterior.
The anterior surface of the pyramid facies anterior partis petrosae, smooth and wide, facing the cranial cavity, directed obliquely from top to bottom and forward and passes into the cerebral surface of the squamous part. It is sometimes separated from the latter by a stony-scaly gap, fissura petrosquamosa. Almost in the middle of the front surface there is an arcuate elevation, eminentia arcuata, which is formed by the anterior semicircular canal of the labyrinth lying under it. Between the elevation and the stony-scaly fissure there is a small platform - the roof of the tympanic cavity, tegmen tympani under which is the tympanic cavity, cavum tympani. On the anterior surface, near the top of the petrous part, there is a small trigeminal depression, impressio trigemini, (place of attachment of the trigeminal node, ganglion trigeminale).
Lateral to the impression is a cleft canal of the large stony nerve, hiatus canalis n. petrosi majoris, from which the narrow groove of the large stony nerve extends medially, sulcus n. petrosi majoris. Anterior and somewhat lateral to the specified hole is a small cleft canal of the small stony nerve, hiatus canalis n. petrosi minoris, from which the furrow of the small stony nerve is directed, sulcus n. petrosi minoris.
Back surface of the pyramid facies posterior partis petrosae, as well as the anterior one, faces the cranial cavity, but goes up and backwards, where it passes into the mastoid process. Almost in the middle of it is a round-shaped internal auditory opening, porus acusticus internus, which leads to the internal auditory canal, meatus acusticus internus(the facial, intermediate, vestibulocochlear nerves pass through it, nn. facialis, intermediate, vestibulocochlearis, as well as the artery and vein of the labyrinth, a. et v. labyrinthi). A little higher and laterally from the internal auditory opening there is a well-defined in newborns, a small depth of the infraarc fossa, fossa subarcuata, (it includes the process of the hard shell of the brain). Even more lateral lies the slit-like outer aperture of the water supply of the vestibule, apertura externa aqueductus vestibuli, opening into the water supply of the vestibule, aqueductus vestibuli. Through the aperture, the endolymphatic duct exits the cavity of the inner ear.
The bottom surface of the pyramid facies inferior partis petrosae, rough and uneven, forms part of the lower surface of the base of the skull. On it is a rounded or oval jugular fossa, fossa jugularis, (place of attachment of the superior bulb of the internal jugular vein).
At the bottom of the fossa, a small furrow is noticeable (the ear branch passes through it vagus nerve). The sulcus leads into the opening of the mastoid tubule, canaliculus mastoideus, which opens in the tympanomastoid fissure, fissura tympanomastoidea.
The posterior edge of the jugular fossa is bounded by the jugular notch, incisura jugularis, which is a small intrajugular process, processus intrajugularis, divides into two parts - anteromedial and posterolateral. Anterior to the jugular fossa lies a rounded opening; it leads to the sleepy canal, ca nalis caroticus, opening at the top of the rocky part.
Between the anterior circumference of the jugular fossa and the external opening of the carotid canal there is a small stony dimple, Fossula petrosa, (place of attachment of the lower node of the glossopharyngeal nerve). In the depths of the dimple there is a hole - a passage into the tympanic tubule, canaliculus tympanies, (the tympanic nerve and the lower tympanic artery pass through it). The tympanic tubule leads to the middle ear auris media, or tympanic cavity, cavum lympani), cavitas tympanies).
Laterally from the jugular fossa, the styloid process protrudes downward and somewhat anteriorly, processus styloideus from which muscles and ligaments begin. Ahead to the outside of the base of the process descends the bone protrusion of the tympanic part - the sheath of the styloid process, vagina processus styloidei. Behind the base of the process there is a stylomastoid opening, foramen stytomastoideum, which is the outlet of the facial canal, canalis facialis.
The top edge of the pyramid marge superior partis petrosae, separates its front surface from the back. A furrow of the superior stony sinus runs along the edge, sulcus sinus petrosi superioris, - the imprint of the superior stony venous sinus lying here and the attachment of the cerebellar tenon - part of the hard shell of the brain. This sulcus passes posteriorly into the sulcus of the sigmoid sinus of the mastoid process of the temporal bone.
The rear end of the pyramid margo posterior partis petrosae, separates its back surface from the bottom. Along it, on the cerebral surface, there is a furrow of the inferior stony sinus, sulcus sinus petrosi inferioris, (trace of the fit of the inferior stony venous sinus). Almost in the middle of the posterior edge, near the jugular notch, there is a triangular funnel-shaped depression in which the outer aperture of the cochlear tubule lies, apertura externa canaliculi cochleae, it ends with a snail tubule, canaliculus cochleae.
The anterior margin of the petrous part, located on the lateral side of its anterior surface, is shorter than the upper and posterior ones; it is separated from the squamous part of the temporal bone by a stony-scaly fissure, fissura petrosquamosa. On it, lateral to the internal opening of the carotid canal, there is an opening of the musculo-tubal canal leading to the tympanic cavity.
Canals and cavities of the petrous part of the temporal bone:
dream channel, canalis caroticus, begins in the middle sections of the lower surface of the stony part with an external opening. At first, the canal goes up, located here in front of the middle ear cavity, then, bending, it follows anteriorly and medially and opens at the top of the pyramid with an internal opening (the internal carotid artery, the accompanying veins and the plexus of sympathetic nerve fibers pass through the carotid canal).
carotid tubules, canaliculi caroticotympanici, are two small tubules that branch off from the carotid canal and lead to the tympanic cavity (the carotid-tympanic nerves pass through them).
face channel, canalis facialis, begins at the bottom of the internal auditory canal, meatus acusticus internus, (in the field of the facial nerve, area n. facialis). The canal runs horizontally and almost at right angles to the axis of the stony part, goes to its front surface, to the cleft of the canal of the large stony nerve, hiatus canalis n. petrosi majoris. Here, turning at a right angle, it forms the knee of the facial canal, geniculum canalis facialis, and passes to the posterior part of the medial wall of the tympanic cavity (respectively, on this wall of the tympanic cavity there is a protrusion of the facial canal, prominentia canalis facialis). Further, the channel, heading backwards, follows along the axis of the rocky part to the pyramidal elevation, eminentia pyramidalis; from here it goes vertically down and opens with a stylomastoid foramen, foramen stylomastoideum, (the facial and intermediate nerves, arteries and veins pass through the canal).
drum string tubule, canaliculus chordae tympani, begins on the outer wall of the facial canal, a few millimeters above the stylomastoid foramen. Heading forward and upward, the tubule enters the tympanic cavity and opens on its back wall (a branch of the intermediate nerve passes through the tubule - the tympanic string, chorda tympani, which, having entered the tympanic cavity through the tubule, leaves it through the stony-tympanic fissure, fissura petrotympanica).
drum tubule, canaliculus tympanicus, begins on the lower surface of the stony part, in the depths of the stony dimple. Then it goes to the lower wall of the tympanic cavity and, perforating it, enters the tympanic cavity, passes along its medial wall and is located in the groove of the cape, sulcus promontorii. Then it follows to the upper wall of the tympanic cavity, where it opens with a cleft canal of the small stony nerve ( hiatus canalis n. petrosi minoris).
musculoskeletal canal, canalis musculotubarius, is a continuation of the anterior upper part of the tympanic cavity. The external opening of the canal is located at the notch between the stony and squamous parts of the temporal bone, at the anterior end of the stony-squamous fissure. The canal is located lateral and slightly posterior to the horizontal part of the carotid canal, almost along the longitudinal axis of the petrous part. Horizontally located septum of the musculo-tubal canal, septum canalis musculotubarii, divides the canal into the upper smaller half-capal of the muscle that strains the eardrum, semi-canals m. tensoris tympani, and the lower greater palucanal of the auditory tube, semicanals lubae auditivae, (in the first lies a muscle that strains the eardrum, the second connects the tympanic cavity with the pharyngeal cavity.
mastoid canal, canaliculus mastoideus, begins in the depths of the jugular fossa, passes across the lower part of the facial canal and opens in the tympanomastoid fissure (the ear branch of the vagus nerve passes through the tubule).
tympanic cavity, cavum tympani. - an elongated, laterally compressed cavity lined with a mucous membrane. Inside the cavity lie three auditory ossicles: hammer, malleus, anvil, incus, and stirrup ( steps), which, articulating with each other, form a chain of auditory ossicles (more about the structure of these canals, the tympanic cavity, the auditory ossicles and the labyrinth.
Tympanic part of the temporal bone
drum part, pars tympanlca, - the smallest section of the temporal bone. It is a slightly curved annular plate and forms the anterior, inferior walls and part of the posterior wall of the external auditory canal, meatus acusticus extenus. Here you can also see the border tympanic-squamous fissure, fissura tympanosquamosa, which, together with the stony-squamous fissure, separates the tympanic part from the mandibular fossa of the squamous part. The outer edge of the tympanic part, closed on top by the scales of the temporal bone, limits the external auditory opening, porus acusticus externus. At the posterior upper outer edge of this hole there is a supra-anal spine, spina suprameatica. Beneath it is the suprapassal fossa, foveola suprameatica. On the border of the larger, inner, and smaller, outer, parts of the external auditory canal, there is a tympanic sulcus, Sulcus tympanicus, (site of attachment of the tympanic membrane). At the top, it is limited by two curved protrusions: in front - a large tympanic spine, spina tympanica major, and behind - a small tympanic spine, spina tympanica minor. Between these protrusions is a tympanic notch ( incisura tympanica) opening into the epitympanic recess, recessus epitympanicus.
Between the medial part of the tympanic part and the squamous part of the temporal bone, the lower process of the roof of the tympanic cavity is wedged. A stony-scaly fissure passes in front of this process, fissura petrosquamosa, and behind - a stony-tympanic fissure, fissura petrotympanica, (a nerve comes out of the latter - a drum string and small vessels). Both furrows continue outwards into the tympanic-squamous fissure, fissura tympanosquamosa.
The lateral part of the tympanic part passes into the stony crest, the elongated part of which forms the sheath of the styloid process, vagina processus styloidei. In a newborn, the external auditory meatus is still absent and the tympanic part is represented by a tympanic ring, anulus tympanicus, which then grows, forming a significant part of the external auditory canal.
On the inner surface of the greater tympanic spine, a spinous crest is clearly distinguishable, at the ends of which there are anterior and posterior tympanic processes, and a furrow of the malleus runs along it.
Parietal bone
Parietal bone, os parietale, steam room, forms the upper and lateral parts of the cranial vault. It has the shape of a quadrangular, convex outwards plate, in which two surfaces are distinguished: outer and inner - four edges: upper, lower, anterior and posterior.Outside surface, facies externa, smooth and convex. The place of the greatest convexity of the bone is the parietal tubercle, tuber parietale. Below the parietal tubercle, an arched, rough upper temporal line runs horizontally, linea temporalis superior, which starts from the anterior edge of the bone and, being a continuation of the line of the same name of the frontal bone, stretches across the entire surface of the parietal bone to its posterior inferior corner. Below this line, parallel to the lower edge of the parietal bone, another, more pronounced lower temporal line passes, linea temporalis inferior, (the first is the site of attachment of the temporal fascia, fascia temporalis, the second - the temporal muscle, m. temporalis).
Inner surface, facies interna, concave; on it there are weakly expressed imprints of the relief of the adjacent brain in the form of finger-like impressions, impressiones digitatae, and tree-like arterial grooves, sulci arteriosi, (traces of adjacent branches of the middle meningeal artery, a. meningea media).
An incomplete groove of the superior sagittal sinus runs along the upper edge of the inner surface of the bone, sulcus sinus sagittalis superioris. With the sulcus of the same name of the other parietal bone, it forms a complete sulcus (a process of the dura mater is attached to the edges of the sulcus - the crescent of the brain, falx cerebri).
In the back of the same upper edge of the bone is a small parietal opening, foramen parietale, through which the branch of the occipital artery passes to the dura mater and the parietal emissary vein. In the depth of the groove of the sagittal sinus and in its neighborhood (especially on the parietal bones in old age) there are many small dimples of granulation, foveolae granulares, (outgrowths come here - granulations of the arachnoid membrane of the brain)).
On the inner surface, at the posterior inferior angle, of the parietal bone lies a deep groove of the sigmoid sinus, sulcus sinus sigmoidei, (imprint of the sigmoid venous sinus of the dura mater). Anteriorly, this groove passes into the temporal bone groove of the same name, posteriorly - into the groove of the transverse sinus of the occipital bone.
superior, sagittal, edge, margosagittalis, straight, strongly serrated, longer than the rest, connects with the same edge of the other parietal bone in the sagittal suture, sutura sagittalis. lower scaly edge, margo squamosus, pointed, arched; its anterior portion is covered by the posterior portion of the upper margin of the greater wing of the sphenoid bone; further posteriorly, the scales of the temporal bone are superimposed with their parietal edge; the most posterior section is connected by teeth with the mastoid process of the temporal bone. Accordingly, these three sections form three seams: a scaly seam, sutura squamosa, parietal mastoid suture, sutura parietomastoidea, and wedge-shaped parietal suture, sutura sphenoparietalis.
Anterior, frontal, edge, margo frontalis, serrated; it connects to the parietal edge of the scales of the frontal bone, forming a coronal suture, sutura coronalis.
Back, occipital, edge, margo occipitalis, serrated, connects with the lambdoid edge of the occipital bone and forms a lambdoid suture, sutura lambdoidea.
Corresponding to the four edges, the parietal bone has four corners:
Anterior superior frontal angle angulus frontalis, approaches a straight line (limited by coronal and sagittal sutures);
anteroinferior wedge-shaped angle, angulus sphenoidalis, acute (limited to coronal and wedge-parietal sutures);
posterior superior occipital angle, angulus occipitalis, obtuse (limited by lambdoid and sagittal sutures).
posterior mastoid angle, angulus mastoideus, more obtuse than the posterior superior (limited to the lambdoid and parietal mastoid sutures); its anterior portion fills the parietal notch, incisura parietalis, temporal bone.
Inferior turbinate
inferior turbinate, concha nasalis inferior, steam room, is a curved bone plate and has three processes: lacrimal and ethmoid.maxillary process, processus maxillaris, forms an acute angle with the bone; this angle includes the lower edge of the maxillary cleft. The process is clearly visible from the side of the maxillary sinus after its opening.
lacrimal process, processus lacrimalis, connects the inferior nasal concha with the lacrimal bone.
lattice process, processus ethmoidalis, departs from the junction of the jaw process with the body of the bone and protrudes into the maxillary sinus. It often fuses with the uncinate process of the ethmoid bone.
The lower shell with the anterior section of the upper edge is strengthened on the shell crest of the upper jaw, crista conchalis maxillae, and the posterior part - on the shell crest of the perpendicular plate of the palatine bone, crista conchalis lamini perpendicularis os palatini. Under the lower shell there is a longitudinal slit - the lower nasal passage, meatus nasi inferior.
lacrimal bone
lacrimal bone, os lacrimale, steam room, is located in the anterior part of the medial wall of the orbit and has the shape of an oblong quadrangular plate. Its upper edge connects with the orbital part of the frontal bone, forming the frontal-lacrimal suture, sutura frontolacrimalis, posterior - with the anterior edge of the orbital plate of the ethmoid bone and forms a cribriform-lacrimal suture, sutura ethmoidolacrimalis. The lower edge of the lacrimal bone on the border with the orbital surface of the upper jaw forms a lacrimal-maxillary suture, sutura lacrimomaxillaris, and with the lacrimal process of the lower concha - the lacrimal-conchal suture, sutura lacrimoconchalis. Anteriorly, the bone joins with the frontal process of the maxilla, forming the lacrimal-maxillary suture, sutura lacrimomaxillaris.The bone covers the anterior cells of the ethmoid bone and carries the posterior lacrimal crest on its lateral surface, crista lacrimalis posterior, which divides it into a posterior section, larger, and an anterior, smaller. The crest ends with a protrusion - a lacrimal hook, hamulus lacrimalis. The latter is directed to the lacrimal sulcus on the frontal process of the upper jaw. The posterior section is flattened, the anterior is concave and forms a lacrimal groove, sulcus lacrimalis. This sulcus, together with the lacrimal sulcus of the upper jaw, sulcus lacrimalis maxillae, forms a fossa of the lacrimal sac, fossa sacci lacrimalis, which continues into the nasolacrimal canal, canalis nasolacrimalis. The channel opens into the lower nasal passage, meatus nasalis inferior.
nasal bone
nasal bone, os nasale, steam room, has the shape of a quadrangle, slightly elongated and somewhat convex anteriorly. Its upper edge is connected with the nasal part of the frontal bone, the lateral edge - with the anterior edge of the frontal process of the upper jaw.The anterior surface of the bone is smooth and perforated by one or more holes (a trace of the passage of vessels and nerves). The posterior surface is slightly concave and has a cribriform groove, Sulcus ethmoidalis, - a trace of the occurrence of the anterior ethmoid nerve. With internal, slightly serrated edges, both nasal bones form an internasal suture, sutura intenasalis, on which the longitudinal groove is located.
Both bones, with their inner surfaces, are adjacent to the nasal spine of the frontal bone and the perpendicular plate of the ethmoid bone.
upper jaw
upper jaw, maxilla, steam room, is located in the upper anterior part of the facial skull. It belongs to the air bones, since it contains a vast cavity lined with a mucous membrane - the maxillary sinus, sinus maxillaris.In the bone, a body and four processes are distinguished.
Body of the upper jaw corpus maxillae, has four surfaces: orbital, anterior, nasal and infratemporal.
The following bone processes are distinguished: frontal, zygomatic, alveolar and palatine.
eye surface, facies orbitalis, smooth, has the shape of a triangle, somewhat inclined anteriorly, outwards and downwards, forms the lower wall of the orbit, orbita.
Its medial edge is connected in front with the lacrimal bone, forming the lacrimal-maxillary suture, posteriorly from the lacrimal bone - with the orbital plate of the ethmoid bone in the ethmoid-maxillary suture and further posteriorly - with the orbital process of the palatine bone in the palatine-maxillary suture.
The anterior margin of the orbital surface is smooth and forms a free infraorbital margin, margo infraorbitalis, being the lower part of the orbital edge of the orbit, margo orbitalis. Outside, it is serrated and passes into the zygomatic process. Medially, the infraorbital margin forms an upward bend, sharpens, and passes into the frontal process, along which the longitudinal anterior lacrimal crest runs, crista lacrimalis anterior. At the point of transition to the frontal process, the inner edge of the orbital surface forms a lacrimal notch ( incisura lacrimalis), which, together with the lacrimal hook of the lacrimal bone, limits the upper opening of the nasolacrimal canal.
The posterior edge of the orbital surface, together with the lower edge of the orbital surface of the large wings of the sphenoid bone, which runs parallel to it, forms the inferior orbital fissure, fissura orbitalis inferior. In the middle part of the lower wall of the gap there is a groove - the infraorbital groove, sulcus infraorbitalis, which, heading anteriorly, becomes deeper and gradually passes into the infraorbital canal, canalis infraorbitalis, (in the furrow and to the pale lie the infraorbital nerve, artery and veins). The channel describes an arc and opens on the anterior surface of the body of the upper jaw. In the lower wall of the canal there are many small openings of the dental tubules - the so-called alveolar openings, foramina alveolaria, through them the nerves pass to the group of anterior teeth of the upper jaw.
infratemporal surface, facies infratemporalis, facing the infratemporal fossa, fossa infratemporalis, and the pterygopalatine fossa, fossa pterygopalatina, uneven, often convex, forms a tubercle of the upper jaw, tuber maxillae. It distinguishes two or three small alveolar openings leading to the alveolar canals, canales alveolares through which the nerves pass to the posterior teeth of the upper jaw.
front surface, fades anterior, slightly curved. Below the infraorbital margin, a rather large infraorbital foramen opens on it, foramen infraorbital, below which there is a small depression - a canine fossa, fossa canina, (here originates the muscle that raises the corner of the mouth, m. levator anguli oris).
Below, the anterior surface without a noticeable border passes into the anterior (buccal) surface of the alveolar process, processus alveolaris, on which there are a number of bulges - alveolar elevations, juga alveolaria.
Inwardly and anteriorly, towards the nose, the anterior surface of the body of the upper jaw passes into the sharp edge of the nasal notch, incisura nasalis. At the bottom, the notch ends with the anterior nasal spine, spina nasalis anterior. The nasal notches of both maxillary bones limit the pyriform aperture ( apertura piriformis) leading to the nasal cavity.
nasal surface, facies nasalis, the upper jaw is more complex. In its upper posterior corner there is a hole - the maxillary cleft, hiatus maxillaris leading to the maxillary sinus. Posterior to the cleft, the rough nasal surface forms a suture with the perpendicular plate of the palatine bone. Here, a large palatine sulcus runs vertically along the nasal surface of the upper jaw, Sulcus palatinus major. It forms one of the walls of the greater palatine canal, canalis palatinus major. Anterior to the maxillary cleft is the lacrimal sulcus, sulcus lacrimalis bounded anteriorly by the posterior margin of the frontal process. The lacrimal bone is adjacent to the lacrimal sulcus at the top, and the lacrimal process of the inferior concha is below. In this case, the lacrimal sulcus closes into the nasolacrimal canal, canalis nasolacrimalis. Even more anteriorly on the nasal surface is a horizontal protrusion - a shell comb, crista conchalis to which the inferior turbinate is attached.
From the upper edge of the nasal surface, at the place of its transition to the anterior, the frontal process straightens upward, processus frontalis. It has medial (nasal) and lateral (facial) surfaces. Lateral surface of the anterior lacrimal crest, crista lacrimalis anterior, divides into two sections - anterior and posterior. The posterior section passes downward into the lacrimal sulcus, sulcus lacrimalis. Its boundary from the inside is the lacrimal edge, margo lacrimalis, to which the lacrimal bone is adjacent, forming with it a lacrimal-maxillary suture, sutura lacrimo-maxillaris. On the medial surface, a cribriform ridge runs from front to back, crista ethmoidalis. The upper edge of the frontal process is serrated and connects with the nasal part of the frontal bone, forming the frontal-maxillary suture, sutura frontomaxillaris. The anterior edge of the frontal process joins with the nasal bone at the naso-maxillary suture, sutura nasomaxillaris.
cheekbone, processus zygomaticus, departs from the outer upper corner of the body. The rough end of the zygomatic process and the zygomatic bone, os zygomaticum, form the zygomatic-maxillary suture, sutura zygomaticomaxillaris.
palatine process, processus palatinus, is a horizontally located bone plate that extends inside from the lower edge of the nasal surface of the body of the upper jaw and, together with the horizontal plate of the palatine bone, forms a bone septum between the nasal cavity and the oral cavity. Both maxillary bones are connected by the internal rough edges of the palatine processes, forming a median palatine suture, sutura palatina mediana. To the right and left of the suture is a longitudinal palatine ridge, torus palatinus.
In the median palatine suture, the palatine processes form a sharp marginal protrusion directed towards the nasal cavity - the so-called nasal crest, crista nosalis, which is adjacent to the lower edge of the vomer and the cartilaginous septum of the nose. The posterior edge of the palatine process is in contact with the anterior edge of the horizontal part of the palatine bone, forming with it a transverse palatine suture, sutura palatina transversa. The upper surface of the palatine processes is smooth and slightly concave. The lower surface is rough, near its posterior end there are two palatine grooves, sulci palatini, which are separated from one another by small palatine awns, spinae palatinae, (vessels and nerves lie in the furrows). The right and left palatine processes at their anterior edge form an oval-shaped incisive fossa, fossa incisiva. There are incisive holes at the bottom of the fossa, foramina incisiva, (two of them), which open the incisal canal, canalis incisivus, also ending with incisive openings on the nasal surface of the palatine processes. The channel can be located on one of the processes, in which case the incisal groove is located on the opposite process. The region of the incisive fossa is sometimes separated from the palatine processes by an incisive suture, sutura incisiva), in such cases, an incisor bone is formed, os incisivum.
Alveolar ridge ( processus alveolaris), the development of which is associated with the development of teeth, departs from the lower edge of the body of the upper jaw downward and describes an arc directed by a bulge forward and outward. The lower surface of this region is the alveolar arch, arcus alveolaris. It has holes - dental alveoli, alveoli dentales, in which the roots of the teeth are located - 8 on each side. The alveoli are separated from one another by alveolar septa. septa interalveolaria. Some of the alveoli are in turn divided by interradicular septa, septa interradicularia, into smaller cells according to the number of tooth roots.
The anterior surface of the alveolar process, corresponding to the five anterior alveoli, has longitudinal alveolar elevations, juga alveolaria. The part of the alveolar process with the alveoli of the two anterior incisors represents a separate incisor bone in the embryo, os incisivum, which merges early with the alveolar process of the upper jaw. Both alveolar processes are connected and form an intermaxillary suture, sutura intermaxillaris.
palatine bone
palatine bone, os palatine- paired bone. It is a curved plate lying in the posterior part of the nasal cavity, making up part of the bottom of this cavity - the bone palate, palatum osseum, and the side wall. It distinguishes between horizontal and perpendicular plates.horizontal plate, lamina horizon-talis, each of the palatine bones, connecting together along the midline of the bone palate, participates in the formation of the posterior part of the median palatine suture, and connecting with the two palatine processes of the maxillary bones lying anteriorly, forms a transverse palatine suture, sutura palatina transversa.
Upper, nasal, surface, facies nasa-lis, the horizontal plate faces the nasal cavity, and the lower one - the palatine surface ( Facies palatina) is part of the bony palate, palatum osseum, the upper wall of the oral cavity itself, cavitas oris propria.
At the posteromedial end of the horizontal plate there is a posterior nasal spine ( spina nasalis posterior, along the medial edge - the nasal crest, crista nasalis. The upper surface of each horizontal plate is slightly concave and smooth, the lower surface is rough.
A thick pyramidal process extends back from the outer section of the base of the perpendicular plate, processus RU- ramidalis. It wedges into the notch between the plates of the pterygoid process of the sphenoid bone and limits the pterygoid fossa from below, fossa pterygoidea.
On the lower surface of the pyramidal process there are 1-2 openings - small palatine openings, foramina palatina mi-By r a, entrances to the lesser palatine canals, canales palatini minores in which the nerves of the same name pass. Anterior to them, along the lateral edge of the horizontal plate, on its lower side, the lower edge of the large palatine sulcus forms a large palatine opening with the same edge of the sulcus on the upper jaw, foramen palatine majus, which is located in the palatine-maxillary suture.
perpendicular plate, lamina re r-pendicularis, the palatine bone forms a right angle with the horizontal plate. This thin bony plate is adjacent to the anterior edge of the medial surface of the pterygoid process and to the posterior part of the nasal surface of the body of the upper jaw. On the maxillary surface Facies ma-xillaris, there is a large palatine sulcus, sul-cus palatinus major, which, with the sulcus of the upper jaw of the same name and the pterygoid process, forms a large palatine canal, canalis palatinus major, opening on the bony palate with a large palatine opening, foramen palatine majus.
On the nasal surface facies nasalis, perpendicular to the plate of the palatine bone, there is a shell crest, crista concha lis, - a trace of fusion with the posterior part of the nasal concha on it.
Slightly higher is a lattice comb ( crista ethmoidalis), where the middle nasal concha of the ethmoid bone has grown.
The upper edge of the perpendicular wall ends in two processes, the orbital process, processus orbitalis, and wedge-shaped c tcom, processus sphenoidalis, which are separated from one another by the sphenopalatine notch, cisura sphenopalatina. The latter, with the body of the sphenoid bone adhering here, forms the sphenopalatine opening, men sphenopalatinum.
eye socket, processus orbitalis, adjacent to the orbital surface in her jaw; there is often a cell on it that connects with the posterior pits of the ethmoid bone.
wedge-shaped process, processus sphenoidalis, approaches the lower surface of the sphenoid bone, its shell and the wings of the vomer.
Cheekbone
Cheekbone, os zygomaticum, steam room, enters from the lateral sections of the facial skull. Three surfaces are distinguished. Outward facing lateral surface, facies lateralis, irregularly quadrangular shaped, convex, especially in the area of the protruding tubercle.Directed inwards and anteriorly concave orbital surface, facies orbitalis, is part of the outer and lower walls of the orbit and converges with the lateral surface with a sharp arcuate edge, complementing the infraorbital edge below, margo infraorbitalis.
temporal surface, facies temporalis, facing the temporal fossa.
From the upper angle of the body of the bone, the frontal process departs, processus frontalis. It connects to the zygomatic process of the frontal bone, forming the fronto-zygomatic suture, sutura frontozygomatica, and with a large wing of the sphenoid bone, making up the sphenoid-zygomatic suture, sutura sphenozygomatica. Along the posterior edge of the upper third of the frontal process of the zygomatic bone, there is a marginal tubercle, tuberculum marginale. On the orbital surface of the frontal process there is often a well-defined orbital eminence, eminentia orbitalis.
Connecting with the upper jaw, the zygomatic bone forms the zygomatic-maxillary suture, sutura zygomaticomaxillaris.
There is a zygomatic-orbital foramen on the orbital surface of the bone, foramen zygomatico-orbital, which leads to a canaliculus bifurcating inside the bone. One branch of this tubule opens on the anterior surface of the bone in the form of a zygomatic-facial opening, foramen zygomaticofaciale, the other - on the temporal surface in the form of a zygomatic-temporal opening (nerves pass through these tubules). On the same surface, the orbital eminence is often expressed, eminentia orbitalis.
The temporal process arises from the posterior angle of the zygomatic bone, processus temporalis. It connects to the zygomatic process of the temporal bone through the temporo-zygomatic suture, sutura temporozygomatica, forming the zygomatic arch, arcus zygomaticus.
Lower jaw
Lower jaw, mandibula, unpaired, forms the lower part of the facial skull. In the bone, a body and two processes, called branches, are distinguished (going upward from the rear end of the body).Body, corpus, is formed from two halves connecting along the midline (chin symphysis, symphysis mentalis), which fuse into one bone in the first year of life. Each half is curved with a bulge outwards. Its height is greater than its thickness. On the body, the lower edge is distinguished - the base of the lower jaw, basis man-dibulae, and the upper one - the alveolar part, pars alveolaris.
On the outer surface of the body, in its middle sections, there is a small chin protrusion ( protuberantia mentalis) outward from which the chin tubercle immediately protrudes, tuberculum mentale. Above and outside of this tubercle lies the mental foramen, foramen mentale, (the exit point of the vessels and nerve). This hole corresponds to the position of the root of the second small molar. Behind the chin opening, an oblique line is directed upward, linea obliqua, which passes into the anterior edge of the lower jaw branch.
The development of the alveolar part depends on the teeth contained in it.
This part is thinned and contains alveolar elevations, juga alveolaria. At the top, it is limited by an arcuate free edge - the alveolar arch, arcus alveolaris. There are 16 (8 on each side) dental alveoli in the alveolar arch, alveoli dentales separated from one another by interalveolar septa, septa interalveolaria.
On the inner surface of the body of the lower jaw, near the midline, there is a single or bifurcated mental spine, spina mentalis, (place of origin of the geniohyoid and subgeniolingual muscles). At its lower edge there is a recess - a digastric fossa, fossa digastrica, trace of attachment of the digastric muscle. On the lateral sections of the inner surface, on each side, in the direction of the branch of the lower jaw, the maxillo-hyoid line passes obliquely, linea mylohyoidea, (here the maxillohyoid muscle and the maxillo-pharyngeal part of the upper constrictor of the pharynx begin).
Above the maxillary-hyoid line, closer to the hyoid spine, is the hyoid fossa, fovea sublingualis, - a trace of the adjacent sublingual gland, and below and posterior to this line - often a weakly expressed submandibular fossa, fovea submandibularis, a trace of the submandibular gland.
branch of the lower jaw, ramus mandibulae, is a wide bone plate that rises from the posterior end of the body of the lower jaw upward and obliquely backward, forming an angle of the lower jaw with the lower edge of the body, angulus mandibulae.
On the outer surface of the branch, in the region of the corner, there is a rough surface - masticatory tuberosity ( tuberositas masseterica) a trace of attachment of the muscle of the same name. On the inner side, respectively, chewing tuberosity, there is a smaller roughness - pterygoid tuberosity, tuberositas pterygoidea, trace of attachment of the medial pterygoid muscle.
In the middle of the inner surface of the branch there is an opening of the lower jaw ( foramen mandibulae) limited from the inside and in front by a small bony protrusion - the uvula of the lower jaw ( Lingula mandibulae). This opening leads to the mandibular canal, canalis mandibulae through which blood vessels and nerves pass. The channel lies in the thickness of the cancellous bone. On the front surface of the body of the lower jaw, it has an exit - the mental hole, foramen mentale.
From the opening of the lower jaw down and forward, along upper bound pterygoid tuberosity, the maxillary-hyoid groove passes, sulcus mylohyoideus, (a trace of the occurrence of the vessels and nerves of the same name). Sometimes this furrow or part of it is covered by a bone plate, turning into a canal. Slightly above and anterior to the opening of the lower jaw is the mandibular ridge, torus mandibularis.
At the upper end of the lower jaw branch there are two processes that are separated by the notch of the lower jaw, incisura mandibulae. Anterior, coronal, process, processes-sus coronoideus, on the inner surface often has a roughness due to the attachment of the temporalis muscle. Posterior, condylar, process, processus condylaris, ends with the head of the lower jaw, caput mandibulae. The latter has an elliptical articular surface, which together with the temporal bone of the skull participates in the formation of the temporomandibular joint, articulatio temporomandibularis.
The head passes into the neck of the lower jaw, collum mandibulae, on the inner floor of the circumference of which a pterygoid fossa is noticeable, fovea pterygoidea, - the place of attachment of the lateral pterygoid muscle.
Hyoid bone
hyoid bone, os hyoideum) lies under the body of the tongue, has the shape of a horseshoe and in thin people can be felt through the skin. Connects to other bones through ligaments. The hyoid bone consists of the body, corpus, and large and small horns, cornua majora and cornua minora.The body of the bone has the form of a plate, convex anteriorly; it bears transverse and vertical ridges. The upper edge of the plate is pointed, the lower one is thickened. The lateral edges of the body are connected to the large horns with the help of articular surfaces either fibrous or hyaline cartilage.
Large horns extend from the body of the bone in the direction of the back and outward. They are thinner and longer than the body and have small thickenings at the ends.
Small horns depart from the junction of the body of the bone with large horns. Sometimes they remain cartilaginous. With the body of the hyoid bone, the small horns are connected either through a joint with a loosely stretched capsule, or with the help of connective tissue. Their ends are enclosed in the stylohyoid ligament, lig. stylohyoideum. This bundle sometimes contains one or more small bones.
Sphenoid bone, os sphenoidale, unpaired, resembles a flying insect, which is the reason for the name of its parts (wings, pterygoid processes).
The sphenoid bone is the product of the fusion of several bones that exist independently in animals, therefore it develops as a mixed bone from several paired and unpaired ossification points, forming 3 parts by the time of birth, which in turn fuse into a single bone by the end of the first year of life.
It has the following parts:
1) body, corpus;
2) big chains, alae majores;
3) small wings,alae minores;
4)pterygoid processes, processus pterygoidei(its medial plate is a former paired pterygoid, develops on the basis of connective tissue, while all other parts of the bone arise on the basis of cartilage).
Sphenoid bone. Back view. 1. Visual channel; 2. Saddle back; 3. Posterior inclined process; 4. Anterior inclined process; 5. Small wing; 6. Superior orbital fissure; 7. Parietal angle; 8. Large wing (cerebral surface); 9. Round hole; 10. Pterygoid canal; 11. Navicular fossa; 12. Lateral plate (pterygoid process); 13. Pterygoid notch; 14. Groove of pterygoid hook; 15. Vaginal process; 16. Wedge-shaped ridge; 17. Body of the sphenoid bone; 18. Medial plate (pterygoid process); 19. Pterygoid hook; 20. Pterygoid fossa; 21. Furrow of the internal carotid artery.
Body, corpus, on its upper surface has a recess along the midline - Turkish saddle, sella turcica, at the bottom of which lies pit For pituitary gland, fossa hypophysialis.In front of her is an elevation, tuberculum sellae, along which it passes transversely sulcus chiasmatis for cross ( chiasma) optic nerves; at the ends sulcus chiasmatis visible visual channels, canales optici through which the optic nerves pass from the cavity of the orbit to the cavity of the skull. Behind the Turkish saddle is limited to a bone plate, saddle back, dorsum sellae. On the lateral surface of the body runs a curved carotid furrow, sulcus caroticus, a trace of the internal carotid artery.
On the front surface of the body, which is part of the posterior wall of the nasal cavity, is visible crest, Crista sphenoidalis, below, entering between the wings of the coulter. Crista sphenoidalis connects in front with a perpendicular plate of the ethmoid bone. Irregularly shaped holes are visible on the sides of the ridge, aperturae sinus sphenoidalis leading to sinus, sinus sphenoidalis, which is placed in the body of the sphenoid bone and is divided septum, septum sinum sphenoidium, into two halves. Through these openings, the sinus communicates with the nasal cavity. In a newborn, the sinus is very small and only around the 7th year of life begins to grow rapidly.
small wings, alae minores, are two flat triangular-shaped plates, which extend anteriorly laterally from the anterior superior edge of the body of the sphenoid bone with two roots; between the roots of small wings are the mentioned visual channels, canales optici. Between the small and large wings is the upper orbital fissure, fissura orbitalis superior leading from the cavity of the skull to the cavity of the orbit.
Big wings, alae majores, depart from the lateral surfaces of the body laterally and upward. near the body, behind fissura orbitalis superior available round hole, foramen rotundum, leading anteriorly to the pterygopalatine fossa, due to the passage of the second branch trigeminal nerve, n. trigemini. Behind, a large wing in the form of an acute angle protrudes between the scales and the pyramid of the temporal bone. Near it there is spinous hole, foramen spinosum through which passes a. meningea media. Much more is visible ahead of him. oval hole, foramen ovale, through which the third branch passes n.trigemini.
Large wings have four surfaces: cerebral,facies cerebralis, orbital,facies orbitalis, temporal, facies temporalis, And maxillary, facies maxillaris. The names of the surfaces indicate the areas of the skull where they face. The temporal surface is divided into the temporal and pterygoid parts by infratemporal crest, crista infritemporalis.
pterygoid processes, processus pterygoidei depart from the junction of the large wings with the body of the sphenoid bone vertically down. Their base is pierced by a sagittally running canal, canalis pterygoideus, - the place of passage of the named nerve and vessels. The anterior opening of the canal opens into the pterygopalatine fossa.
Each process consists of two plates - lamina medialis And lamina lateralis, between which a fossa is formed at the back, fossa pterygoidea.
The medial plate is bent down crochet, hamulus pterygoideus, through which the tendon starting on this plate is thrown m. tensor veli palatini(one of the muscles of the soft palate).
Sphenoid bone. Front view. 1. Aperture of the sphenoid sinus; 2. Saddle back; 3. Wedge-shaped shell; 4. Small wing; 5. Superior orbital fissure; 6. Cheekbone; 7. Infratemporal surface, 8. Sphenoid spine; 9. Pterygopalatine sulcus; 10. Lateral plate; 11. Pterygoid hook; 12. Medial plate of the pterygoid process; 13. Vaginal process; 14. Wedge-shaped comb; 15. Pterygoid notch; 16. Pterygoid canal; 17. Round hole; 18. Infratemporal crest; 19. Orbital surface of the greater wing; 20. Temporal surface of the greater wing.
Variants and anomalies
Non-union of the anterior and posterior halves of the body of the sphenoid bone leads to the formation of a narrow, so-called craniopharyngeal canal in the center of the Turkish saddle. The oval and spinous foramen sometimes merge into one common foramen, there may be no spinous foramen.
Sphenoid bone, os sphenoidale, unpaired, forms the central section of the base.
The middle part of the sphenoid bone is the body, corpus, cubic in shape, has six surfaces. On the upper surface, facing the cranial cavity, there is a recess - the Turkish saddle, sella turcica, in the center of which is the pituitary fossa, fossa hypophysialis. It contains the pituitary gland, hypophysis. The size of the fossa depends on the size of the pituitary gland. The border of the Turkish saddle in front is the tubercle of the saddle, tuberculum sellae. Behind it, on the lateral surface of the saddle, there is an unstable middle inclined process, processus clinoideus medius.
Anterior to the tubercle of the saddle is a shallow transverse precross groove, sulcus prechiasmatis. Behind her lies the visual cross, chiasma opticum. Laterally, the groove passes into the optic canal, canalis opticus. Ahead of the furrow is a smooth surface - a wedge-shaped elevation, jugum sphenoidale, connecting the small wings of the sphenoid bone. The front crane of the upper surface of the body is serrated, protrudes slightly forward and connects with the posterior edge of the cribriform plate, forming a wedge-ethmoid suture, sutura spheno-ethmoidalis. The back border of the Turkish saddle is the back of the saddle, dorsum sellae, which ends on the right and left with a small posterior inclined process, processus clinoideus posterior.
On the sides of the saddle from back to front there is a carotid groove, sulcus caroticus (a trace and the accompanying nerve plexus). At the posterior edge of the furrow, on its outer side, a pointed process protrudes - a wedge-shaped tongue, lingula sphenoidalis.
The back surface of the back of the saddle passes into the upper surface of the basilar part, forming a slope, clivus (the bridge, medulla oblongata, basilar artery and its branches lie on it). The rear surface of the body is rough; through the cartilaginous layer, it connects to the anterior surface of the basilar part of the occipital bone and forms wedge-occipital synchondrosis, synchondrosis spheno-occipitalis. As we age, cartilage is replaced by bone tissue and both bones fuse together.
The anterior surface of the body and part of the lower face into the nasal cavity. A wedge-shaped ridge protrudes in the middle of the anterior surface, crista sphenoidalis; its front edge is adjacent to the perpendicular plate of the ethmoid bone. The lower process of the crest is pointed, extended downwards and forms a wedge-shaped beak, rostrum sphenoidale. The latter connects with the wings, alae vomeris, forming a vomer-beak canal, canalis vomerorostratis, lying along the midline between the upper edge of the vomer and the wedge-shaped beak. Lateral to the ridge lie thin curved plates - wedge-shaped shells, conchae sphenoidales. The shells form the anterior and partly the lower walls of the sphenoid sinus, sinus sphenoidalis. Each shell has a small opening - the aperture of the sphenoid sinus, apertura sinus sphenoidalis. Outside of the aperture, there are small depressions that cover the cells of the posterior part of the labyrinth of the ethmoid bone. The outer edges of these recesses are partially connected to the orbital plate of the ethmoid bone, forming a sphenoid-ethmoid suture, sutura spheno-ethmoidalis, and the lower ones - with the orbital process, processus orbitalis, of the palatine bone.
The sphenoid sinus, sinus sphenoidalis, is a paired cavity that occupies most of the body of the sphenoid bone; it belongs to the air-bearing paranasal sinuses. The right and left sinuses are separated from one another by the septum of the sphenoid sinuses, septum sinuum sphenoidalium. which anteriorly continues into the wedge-shaped ridge. As in the frontal sinuses, the septum is often asymmetrical, as a result of which the size of the sinuses may not be the same. Through the aperture of the sphenoid sinus, each sphenoid sinus communicates with the nasal cavity. The cavity of the sphenoid sinus is lined with a mucous membrane.
Lesser wings, alae minores, of the sphenoid bone extend on both sides from the anterior superior corners of the body in the form of two horizontal plates, at the base of which there is a rounded opening. From this hole begins a bone canal up to 5-6 mm long - the visual canal, canalis opticus. It contains the optic nerve, n. opticus, and ophthalmic artery, a. ophthalmica, Small wings have an upper surface facing the cranial cavity, and a lower surface directed into the cavity of the orbit and closing the upper orbital fissure from above, fissura orbitalis superior.
The anterior margin of the lesser wing, thickened and serrated, connects to the orbital part. The posterior edge, concave and smooth, protrudes freely into the cranial cavity and is the boundary between the anterior and middle cranial fossae, fossae cranii anterior et media. Medially, the posterior edge ends with a protruding, well-defined anterior inclined process, processus clinoideus anterior (part of the dura mater is attached to it - the diaphragm of the Turkish saddle, diaphragma sellae).
Large wings, alae majores, depart from the lateral surfaces of the body of the sphenoid bone and go outward.
The large wing has five surfaces and three edges. The upper cerebral surface, facies cerebralis, is concave, facing the cranial cavity. It forms the anterior part of the middle cranial fossa. Finger-like impressions stand out on it, impressiones digitatae, and arterial grooves, sulci arteriosi (imprints of the relief of the adjacent surface of the brain and middle meningeal arteries).
There are three permanent openings at the base of the wing: a round opening, foramen rotundum, is located inward and anteriorly (the maxillary nerve, n maxillaris, exits through it); outside and behind the round hole is an oval hole, foramen ovale (it passes the mandibular nerve, n. mandibularis), and outside and behind the oval hole is a spinous hole, foramen spinosum (the middle meningeal artery, vein and nerve come through it). In addition, non-permanent holes occur in this area. One of them is the venous opening, foramen venosum, located somewhat posterior to the foramen ovale. It passes the vein going from the cavernous sinus to the pterygoid venous plexus. The second is the stony opening, foramen petrosum, through which the small stony nerve passes, the pterygofrontal suture, sutura sphenofrontalis. The outer sections of the frontal edge end with a sharp parietal edge, margo parietalis, which, with a wedge-shaped angle to the theme of another bone, forms a wedge-parietal suture, sutura sphenoparietalis. The internal sections of the frontal margin pass into a thin free margin, which is separated from the lower surface of the lesser wing, limiting the superior orbital fissure from below.
The anterior zygomatic margin, margo zygomaticus, is serrated. The frontal process, processus frontalis, the zygomatic bone and the zygomatic edge are connected, forming a sphenoid-zygomatic suture, sutura sphenozygomatica.
The posterior scaly edge, margo squamosus, connects to the wedge-shaped edge, margo sphenoidalis, and forms a wedge-scaly suture, sutura sphenosquamosa. Posteriorly and outwardly, the scaly edge ends with the spine of the sphenoid bone (the place of attachment of the sphenomandibular ligament, lig sphenomandibularis, and bundles, straining the palatine curtain, m. tensor veli palatini).
Inward from the spine of the sphenoid bone, the posterior edge of the large wing lies in front of the stony part, pars petrosa, of the temporal bone and limits the sphenoid-stony fissure, fissura sphenopetrosa, medially passing into a torn hole, foramen la-lacerum; on a non-macerated skull, this gap is filled with cartilaginous tissue and forms wedge-stony synchondrosis, synchondrosis sphenopetrosa.
Pterygoid processes, processus pterygoidei, depart from the junction of the large wings with the body of the sphenoid bone and go down. They are formed by two plates - lateral and medial. The lateral plate, lamina lateralis (processus pterygoidei), is wider, thinner and shorter than the medial one (the lateral pterygoid muscle, m. pterygoideus lateralis, starts from its outer surface).
The medial plate, lamina medialis (processus pterygoidei), is narrower, thicker and slightly longer than the lateral one. Both plates grow together with their front edges and, diverging posteriorly, limit the pterygoid fossa, fossa pterygoidea (the medial pterygoid muscle, m. pterygoideus medialis, begins here). In the lower finished
both plates do not fuse and limit the pterygoid notch, incisura pterygoidea. It contains the pyramidal process, processus pyramidalis, of the palatine bone. The free end of the medial plate ends with a pterygoid hook directed downward and outward, hamulus pterygoideus, on the outer surface of which there is a furrow of the pterygoid hook, sulcus hamuli pterygoidei (the tendon of the muscle that strains the palatine curtain, m. tensor veli palatini, is thrown through it).
The posterior superior edge of the medial plate expands at the base and forms a navicular fossa, fossa scaphoidea, of a wadded shape.
Outside of the scaphoid fossa, there is a shallow furrow of the auditory tube, sulcus tubae auditivae, which laterally passes to the lower surface of the posterior edge of the large wing and reaches the spine of the sphenoid bone (the cartilaginous part of the auditory tube is adjacent to this groove). Above the scaphoid fossa and medially there is an opening with which the pterygoid canal begins, canalis pterygoideus (vessels and nerves pass through it).
The canal runs in the sagittal direction in the thickness of the base of the pterygoid process and opens on the maxillary surface of the greater wing, on the posterior wall of the pterygopalatine fossa.
The medial plate at its base passes into a flat, horizontally directed vaginal process, processus vaginalis, which is located under the body of the sphenoid bone, covering the side of the vomer wing, ala vomeris. At the same time, the furrow of the vaginal process facing the wing of the vomer, the vomerovaginal sulcus, sulcus vomerovaginalis, turns into the vomerovaginal canal, canalis vomerovaginalis.
Outside of the process there is a sagittally running small palatovaginal groove, sulcus palatovaginalis. The sphenoid process of the palatine bone adjacent to the bottom, processus sphenoidalis ossis palatini, closes the groove into the canal of the same name, canalis palatovaginalis (the nerve branches of the pterygopalatine ganglion pass through the vomerovaginal and palatovaginal canals, and in the palatovaginal canal, in addition, the branches of the sphenoid-palatine arteries).
Sometimes, from the posterior edge of the outer plate towards the spine of the sphenoid bone, the pterygoid process, processus pterygospinosus, is directed, which can reach the indicated spine and form a hole.
The anterior surface of the pterygoid process is connected to the posterior surface of the upper jaw in the region of the medial edge of the tubercle, forming the sphenomaxillary suture, sutura sphenomaxillaris, which lies deep in the pterygopalatine fossa.
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Sphenoid bone, os sphenoidale, unpaired, located in the middle of the base of the skull. It connects with many bones of the skull and takes part in the formation of a number of bone cavities, cavities, and to a small extent in the formation of the roof of the skull. The shape of the sphenoid bone is peculiar and complex. 4 parts are distinguished in it: the body, corpus, and three pairs of processes, of which two pairs are directed to the sides and are called small wings, alae minora, and large wings, alae majora. The third pair of processes, pterygoid, processus pterygoidei, is turned downwards.
The body makes up the middle part of the bone and has an irregular shape, close to a cube, in which 6 surfaces are distinguished. In the body there is a sphenoid sinus, sinus sphenoidalis, filled with air. Therefore, the sphenoid bone belongs to the pneumatic bones. The posterior surface of an approximately quadrangular shape fuses with the main part of the occipital bone in children through cartilage, in adults through bone tissue. The anterior surface of the body faces the posterior upper part of the nasal cavity, adjoining the posterior bone cells of the ethmoid bone. A wedge-shaped ridge, crista sphenoidalis, passes along the midline of this surface, to which the perpendicular plate of the ethmoid bone is adjacent. The wedge-shaped crest passes below into the wedge-shaped beak, rostrum sphenoidale. On both sides of the crista sphenoidalis are the openings of the sphenoid sinus, aperturae sinus sphenoidalis, individually different in shape and size. The front surface at an angle passes into the lower, bearing in the middle the already mentioned wedge-shaped beak. The anterior part of the lower surface and the lower part of the anterior are formed by thin triangular bone plates, shells of the sphenoid bone, conchae sphenoidales, which limit the lower and partly outer edges of the apertura sinus sphenoidalis. In young, the wedge-shaped shells are connected to the rest of the body by a suture and are somewhat mobile. The lateral surfaces of the body in the middle and lower parts are occupied by the base of large and small wings. The upper part of the lateral surfaces is free and on each side there is a groove of the carotid artery, sulcus caroticus, along which the internal carotid artery passes.
Figure: Sphenoid bone, dorsal view.
1 - small wing; 2 - body of the sphenoid bone; 3 - furrow of the intersection of the optic nerves; 4 - fossa of the epididymis; 5 - visual channel; c - superior orbital fissure; 7 - round hole; 8 - cerebral surface of large wings; 9 - oval hole; 10 - spinous opening; 11 - back of the Turkish saddle; 12 - a large wing.
Behind and laterally, the edge of the furrow forms a protrusion - a wedge-shaped tongue, lingula sphenoidalis. The upper surface, facing the cranial cavity, has a depression in the middle, called the Turkish saddle, sella turcica. At the bottom of it is the pituitary fossa, fossa hypophysialis, in which the pituitary gland is placed. In front and behind the saddle is limited by protrusions, the anterior of which is represented by a tubercle of the saddle, tuberculum sellae, and the rear by a high ridge called the back of the saddle, dorsum sellae. The back surface of the back of the saddle continues into the upper surface of the main part of the occipital bone, forming a slope, clivus. The corners of the back of the Turkish saddle are extended downward and backward in the form of posterior deviated processes, processus clinoidei posteriores. Behind the tuberculum sellae on each side is the median deviated process, proceccus clinoideus medius. In front of the tubercle of the saddle there is a transversely running shallow furrow of the chiasm, sulcus chiasmatis, where the optic chiasm is located.
The small wings of the sphenoid bone, alae minora, depart from the body on each side with two roots. Between them is the optic canal, canalis opticus, through which the optic nerve and ophthalmic artery. Small wings of a flat shape are directed horizontally outward and either connected with large wings or terminate separately from them. The upper surface of the wings faces the cranial cavity, the lower surface faces the orbit. The anterior serrated edge of the wings is connected to the frontal bone, while the posterior smooth edge protrudes into the cranial cavity: an anterior deviated process, processus clinoideus anterior, is formed on it on each side. The lower surface of the small wings, together with the large wings, limits the upper orbital fissure, fissura orbitalis superior, through which the oculomotor, trochlear, ophthalmic and abducens nerves and the superior ophthalmic vein pass.
Large wings, alae majora, depart from each side of the lower-lateral sections of the body of the sphenoid bone, spreading outwards and upwards. They have 4 surfaces and 4 edges. The cerebral surface, facies cerebralis, faces the cranial cavity, is concave, has cerebral elevations and digital impressions. Medially, 3 holes are defined on it: round, foramen rotundum, oval, foramen ovale, and spinous, foramen spinosum, penetrating the wing through. Posteriorly, the large wings end in a sharp protrusion, an angular spine, spina angularis. The temporal surface, facies temporalis, external, is divided by a transversely running infratemporal crest, crista infratemporalis, into two surfaces, of which the upper one participates in the formation of the temporal fossa, the lower one passes to the base of the skull and takes part in the formation of the infratemporal fossa. The orbital surface, facies orbitalis, faces forward, forms the posterior part of the outer wall of the orbit. The maxillary surface, facies maxillaris, faces the upper jaw. The edges of the large wings are connected to the squamous part of the temporal bone, with the zygomatic bone, parietal and frontal. The marginal names correspond to the adjacent bones, margo squamosus, margo zygomaticus, margo parietalis, and margo frontalis.
Figure: Sphenoid bone, front view.
1 - large wing; 2 - small wing; 3 - lateral plate of the pterygoid process; 4 - body of the sphenoid bone; 5 - wedge-shaped ridge; 6 - pterygoid channel; 7 - medial plate of the pterygoid process; 8 - pterygoid fossa; 9 - pterygoid hook; 10 - pterygoid fossa; 11 - round hole; 12 - orbital surface of the large wing; 13 - upper orbital fissure; 14 - visual channel; 15 - opening of the sphenoid sinus.
Pterygoid processes, processus pterygoidei, depart from the sphenoid bone at the junction of the body with large wings and consists of medial and lateral plates, laminae medialis et laminae lateralis. In front, both plates are connected, and behind they are separated from each other by a deep pterygoid fossa, fossa pterygoidea. Below, between both plates, there is a pterygoid notch, incisura pterygoidea, which includes the processus pyramidalis of the palatine bone. On the anterior surface of the pterygoid processes there is a large palatine groove, sulcus palatinus major, which, when connected to the corresponding grooves of neighboring bones (palatine and maxillary), turns into a large palatine canal, canalis palatinus major. At the base of the pterygoid process in the anterior-posterior direction is the pterygoid canal, canalis pterygoideus. The lateral plate is shorter, but wider than the medial one, and is part of the infratemporal fossa. The medial plate ends below with a curved pterygoid hook, hamulus pterygoideus. In the upper part of the posterior edge of the medial plate there is a navicular fossa, fossa scaphoidea, which serves to attach m. tensoris veli palatini, and the cartilaginous part of the auditory tube is adjacent to its upper section.
The sphenoid sinus is divided by a septum, septum sinuum sphenoidalium, into two unequal parts. The sinus opens into the nasal cavity through openings on the anterior surface of the body of the sphenoid bone.
Ossification. The development of the sphenoid bone comes from 4 ossification points that arise in the anterior and posterior parts of the body, in each of the processes; in addition, there are separate ossification points in the medial plate of the pterygoid processes and in the conchae sphenoidales. Ossification points appear first in the 2nd month of embryonic development in the large wings, and in the 3rd month, all the rest, except for the conchae sphenoidales, where they appear after birth. At the 6-7th month of intrauterine development, small wings are connected to the anterior half of the body of the sphenoid bone. By the end of the intrauterine period, the anterior and posterior parts of the body merge. Large wings and sphenoid processes are connected to the body of the bone at the end of the 1st year after birth. The sphenoid sinus in newborns is small and reaches full development in the 6th year of life. The connection of the body of the sphenoid bone with the main part of the occipital bone occurs between 16 and 20 years, more often at 16-18 years.
