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(os occipitale), unpaired, participates in the formation of the back of the base and the vault of the skull (Fig. 1). It distinguishes the basilar part, 2 lateral parts and scales. All these parts, connecting, limit large hole (foramen magnum).
Rice. one.
a - topography of the occipital bone;
6 - outside view: 1 - external occipital protrusion; 2 - the highest protruding line; 3 - upper vynynaya line; 4 - lower vynynaya line; 5 - condylar canal; 6 - occipital condyle; 7 - intrajugular process; 8 - basilar part of the occipital bone; 9 - pharyngeal tubercle; 10 - lateral part of the occipital bone; 11 - jugular notch; 12 - jugular process; 13 - condylar fossa; 14 - a large hole; 15 - external occipital crest; 16 - occipital scales;
c - inside view: 1 - groove of the superior sagittal sinus; 2 - internal occipital protrusion; 3 - internal occipital crest; 4 - a large hole; 5 - groove of the sigmoid sinus; 6 - furrow of the lower stony sinus; 7 - slope; 8 - basilar part of the occipital bone; 9 - lateral part of the occipital bone; 10 - jugular tubercle; 11 - jugular process; 12 - cruciform elevation; 13 - groove of the transverse sinus; 14 - scales of the occipital bone;
d - side view: 1 - lateral part of the occipital bone; 2 - slope; 3 - basilar part of the occipital bone; 4 - furrow of the lower stony sinus; 5 - pharyngeal tubercle; 6 - channel hypoglossal nerve; 7 - jugular process; 8 - occipital condyle; 9 - condylar canal; 10 - condylar fossa; 11 - a large hole; 12 - occipital scales; 13 - lambdoid edge of the occipital scales; 14 - mastoid edge of the occipital scales
Basilar part(pars basilaris) fuses with the body in front sphenoid bone(up to 18-20 years of age, they are connected by cartilage, which subsequently ossifies). In the middle of the lower surface of the basilar part there is pharyngeal tubercle (tuberculum pharyngeum), to which the initial part of the pharynx is attached. The upper surface of the basilar part faces the cranial cavity, is concave in the form of a groove, and together with the body of the sphenoid bone forms a slope (clivus). The medulla oblongata, pons, vessels and nerves are adjacent to the slope. On the lateral edges of the basilar part there is furrow of the lower stony sinus (sulcus sinus petrosi inferioris)- the place of attachment of the venous sinus of the same name of the dura mater.
Lateral part(pars lateralis) connects the basilar part with the scales and limits the large opening on the lateral side. On the lateral edge there is jugular tenderloin (incisura jugularis), which with the corresponding notch temporal bone limits the jugular foramen. Along the edge of the notch is intrajugular process (processus intrajugularis); it divides the jugular foramen into anterior and posterior sections. In the anterior section passes the internal jugular vein, in the back - IX-XI pairs cranial nerves. The posterior jugular notch is limited by the base jugular process (processus jugularis), which faces the cranial cavity. On the inner surface of the lateral part, posterior and medial from the jugular process, there is a deep sulcus of the sigmoid sinus. In the anterior part of the lateral part, on the border with the basilar part, is located jugular tubercle, tuberculum jugulare, and on the lower surface occipital condyle (condylus occipitalis), by which the skull is connected to the I cervical vertebra. Behind each condyle is condylar fossa (fossa condylaris), at its bottom there is an opening of the emissary vein (condylar canal). The base of the condyle is pierced canal of the hypoglossal nerve (canalis nervi hypo-glossi) through which the corresponding nerve passes.
Occipital scales(squama occipitalis) has an upper lambdoid (margo lambdoideus) and lower mastoid margin (margo mastoideus). Outside surface the scales are convex, in its middle is external occipital protuberance (protuberantia occipitalis externa). Down towards the big hole, it continues into external occipital crest (crista occipitalis externa). Perpendicular to the ridge are the upper and lower nuchal lines (lineae nuchalis superior et inferior). Sometimes the highest nuchal line (linea nuchalis suprema) is also noted. Muscles and ligaments are attached to these lines.
Inner surface the occipital scale is concave, has an internal occipital protrusion (protuberantia occipitalis interna) in the center, which is the center cruciform elevation (eminentia cruciformis). Up from the internal occipital protrusion departs sulcus of the superior sagittal sinus, down - internal occipital crest (crista occipitalis interna), and to the right and left - grooves of the transverse sinus (sulci sinui transversi).
Ossification: at the beginning of the 3rd month prenatal development 5 ossification points appear: in the upper (membranous) and lower (cartilaginous) parts of the scales, one in the basilar, two in the lateral parts. By the end of this month, the upper and lower parts of the scales grow together, in the 3-6th year the basilar, lateral parts and scales grow together.
Human Anatomy S.S. Mikhailov, A.V. Chukbar, A.G. Tsybulkin
Atlantococcipital joint, articulatio atlanto-occipitalis (Fig.,,; see Fig.,), paired. Formed articular surface Yu occipital condyles, condyli occipitales, and superior articular fossa atlas, fovea articularis superior. The longitudinal axes of the articular surfaces of the occipital bone and the atlas converge anteriorly somewhat. The articular surfaces of the occipital bone are shorter than the articular surfaces of the atlas. The articular capsule is attached along the edge of the articular cartilage. According to the shape of the articular surfaces, this joint belongs to the group ellipsoid, or condylar, joints.
In both, right and left, joints that have separate joint capsules, movements are performed simultaneously, that is, they form one combined joint; nodding (bending forward and backward) and slight lateral movements of the head are possible.
This connection is different:
- Per single atlantooccipital membrane, membrana atlanto-occipitalis anterior(see fig. , ). Stretches throughout the gap between the anterior edge of the foramen magnum and the upper edge of the anterior arch of the atlas; grows together with the upper end of lig. longitudinal anterius. Behind her is anterior atlantooccipital ligament, lig. atlanto-occipitalis anterior stretched between occipital bone and the middle part of the anterior arch of the atlas.
- Posterior atlantooccipital membrane, membrana atlanto-occipitalis posterior(see fig. , , ). It is located between the posterior edge of the foramen magnum and the upper edge of the posterior arch of the atlas. In the anterior section it has a hole through which the vessels and nerves pass. This membrane is a modified yellow ligament. The lateral parts of the membrane are lateral atlantooccipital ligaments, ligg. atlanto-occipitalis lateralia.
When the atlas and the axial vertebra are articulated, three joints are formed - two paired and one unpaired.
Lateral atlantoaxial joint (see Fig.,), paired, formed by the lower articular surfaces of the atlas and the upper articular surfaces of the axial vertebra. It belongs to the type of inactive joints, since its articular surfaces are flat and even. In this joint, sliding occurs in all directions of the articular surfaces of the atlas in relation to the axial vertebra.
Median atlantoaxial joint, articulatio atlanto-axialis mediana (see fig. , , , ;), is formed between the posterior surface of the anterior arch of the atlas (fovea dentis) and the tooth of the axial vertebra. In addition, the posterior articular surface of the tooth forms a joint with .
The joints of the tooth belong to the group of cylindrical joints. In them, it is possible to rotate the atlas together with the head around the vertical axis of the tooth of the axial vertebra, i.e., turning the head to the right and left.
The ligamentous apparatus of the median atlantoaxial joint includes:
- Integumentary membrane, membrana tectoria(see fig.,,;), which is a wide, rather dense fibrous plate stretched from the anterior edge of the large occipital foramen to the body of the axial vertebra. This membrane is called integumentary, because it covers the back (from the side of the spinal canal) of the tooth, the transverse ligament of the atlas and other formations of this joint. It is considered as part of the posterior longitudinal ligament of the spinal column.
- cruciate ligament Atlanta, lig. cruciforme atlantis(see fig.), consists of two beams - longitudinal and transverse. The transverse bundle is a dense connective tissue cord stretched between the inner surfaces of the lateral mass of the atlas. It is adjacent to the posterior articular surface of the tooth of the axial vertebra and strengthens it. This bundle is called transverse ligament of the atlas, lig. transversum atlantis(see fig.
The skull is an important part of the body, it protects the brain, vision and other systems, is formed by connecting various bones. The occipital bone is one of the arch-forming elements and part of the base of the skull; it does not have a pair. It is located next to the sphenoid, temporal and parietal bones. The outer surface is convex, and the reverse (brain) part is concave.
The structure of the occipital bone
The occipital bone consists of four different sections. It is of mixed origin.
Bone is made up of:
- Scales.
- Articular condyles.
- main body.
- A large opening that is located between the scales, condyles and body. Serves as a passage between the spine and the cranial cavity. The shape of the hole is ideal for the first cervical vertebra- Atlas, which allows you to achieve the most successful interaction.
It should be noted that if for the human body the occipital bone is unified system, then in animals it may consist of several interconnected bones or elements.
Scales of the occipital bone
The scales of the occipital bone outwardly resemble a plate, part of a sphere in the form of a triangle. It is concave on one side and convex on the other. Due to the attachment of various muscles and ligaments to it, it has a rough relief.
From the outer, convex part, are located:
- The protruding part or external tubercle of the occiput. characteristic feature is that it can be felt when probing and pressing on the occipital region of the human head. It begins with bone ossification.
- From the most protruding part, two lines go in the lateral direction, one on each side. The one between the lower and upper edge is called the “upper notch line”. Above it, starting from upper bound, the highest line originates.
- The external crest of the occiput begins at the site of ossification and continues along the midline to the posterior border of the foramen magnum.
- In the outer crest of the occiput, the lower nuchal lines originate.
The inner region reflects the shape of the brain and the places of attachment of its membranes to the areas of the occipital bone. Two ridges divide the concave surface into four different sections. The intersection of both ridges was called the "cross-shaped hill". The center of the intersection is known as the internal occipital protuberance.
Lateral sections of the occipital bone
The lateral parts are located between the scales and the body, they are responsible for the connections of the entire skull and spinal column. For this, condyles are located on them, to which the first cervical vertebra, the atlas, is attached.
They are also responsible for limiting the large occipital foramen, forming its lateral parts.
Body or main region of the occipital bone
The main characteristic is that as they grow older, this bone is firmly fused with the sphenoid bone of the human skull. The process is completed by the age of seventeen or twenty.
The densest part resembles a regular quadrangle in its shape. Its extreme region is one of the sides of the large occipital foramen. In childhood, it has cracks filled with cartilaginous tissues. With age, the cartilage component hardens.
Development of the occipital bone
intrauterine development.
During fetal development, the occipital bone includes:
- Occiput - everything that is located below the upper cut-out line. Belongs to the cartilaginous type. It has 6 ossified areas.
- Scales - the rest of the occipital bone, located above the line. It has 2 ossification points. Ossification points are the places from which the formation of bone tissue begins.
Neonatal period.
Before birth and for some time after, the bone consists of 4 elements, which are separated from each other by cartilage. These include:
- base part or base;
- anterior condyles;
- posterior condyles;
- scales.
After birth, the process of ossification begins. This means that cartilage begins to be replaced by bone tissue.
After 4-6 years.
There is a fusion of certain parts of the occiput. The fusion of the condyles and the base of the occipital bone lasts for about 5-6 years.
Anomalies in the development of the occipital bone
Developmental anomalies include:
- incomplete or absolute union of the condyles with the atlas;
- change in the mass of the occipital protrusion;
- the appearance of new, extra bones, processes, condyles and sutures.
Fractures of the occipital bone, their consequences and symptoms
The main causes of violation of the integrity of the occipital bone:
- Accidents. The fracture occurs as a result of the impact of the airbag.
- The fall. Most often as a result of ice.
- Weapon wounds.
- May occur with injuries to neighboring bones;
- An injury caused by a deliberate blow to the back of the head.
At the site of the fracture, obvious edematous phenomena and a hematoma are formed on the skin. Depending on the type of impact, there are direct and indirect fractures:
- Direct. The fracture is caused by direct traumatic impact (gunshot, blow, etc.). Most injuries are of the direct type.
- Indirect, when the main force that caused the violation of the integrity of the bone falls on other areas.
There is also a classification based on the type of damage:
- Depressed fractures. They are formed from the action of a blunt object on the occipital bone. AT this case turns out negative impact on the brain and its injury. Edema and hematomas are formed.
- The most terrible is a splinter-type fracture, with this option significant brain damage occurs.
- A linear fracture is safer and less traumatic. A person may not even be aware of it. Statistically, it is more typical for childhood due to restlessness and high activity.
To determine the presence of a fracture, familiarize yourself with the main symptoms:
- migraine;
- significant pain in the back of the head;
- the reaction of pupils to a light stimulus is disturbed;
- functioning problems respiratory system organism;
- fainting and clouding of consciousness.
If you have two, three or more symptoms, see your doctor. Remember that an improperly fused bone can adversely affect your health. In a shrapnel wound, small parts of the bone can lead to lethal outcome or brain dysfunction. Fractures of any skull bone can lead to death, but the occipital bone is in direct contact with the active centers of the brain and its membranes, which increases the risk.
How to treat a skull fracture?
If the doctor did not find hematomas or brain dysfunction, then special intervention in the fusion process is not required, and surgical intervention can be dispensed with. Just follow general recommendations as in a fracture or severe bruise head bones.
- It is necessary to treat the damaged area. In the absence of allergies to drugs, painkillers can be used. Don't tolerate pain because painful sensations a person strains, which has a bad effect on damaged bones.
- It is advisable not to be alone and analyze your pastime. At the first sign of falling out of reality, amnesia or loss of consciousness, call an ambulance.
- If a large displacement of the bone was revealed on the examination and images, then the method of surgical intervention will have to be used. The sharp edges of the fracture can damage the brain and contribute to epilepsy or other diseases. If the patient is a child under the age of three, then during the period of growing up, the fracture site may begin to diverge. To eliminate the violation requires the intervention of a surgeon.
Occipital bone bruises
In this case most of damage falls on soft tissues head, and the impact on the bone is minimal. If you suspect a bruise, you need to make sure that there is no concussion. How to do it? First of all, a sign of the absence of a concussion is that the person did not faint at the time of the injury. If you are not sure that you remained conscious or if you have a memory gap, be sure to see a doctor, you may have a concussion or a fracture.
The consequences of a bruise are less frightening than those of a fracture, but still they are.
These include:
- problems with the processing of visual information, inaccuracy of vision or its sharp deterioration;
- feelings of nausea and vomiting;
- memory impairment, problems concentrating;
- migraines, pain various parts heads;
- problems with falling asleep and sleeping;
- deterioration of the psychological state.
Treatment of bone bruises
In order for there to be no consequences in the future, it is necessary to remember the date of the bruise, and notify your neurologist about this. This will help control the healing of the injury and prevent complications in the future. Also, this point must be taken into account when collecting an anamnesis, since any damage to the head can affect through large gap time.
After a soft tissue injury, a person needs a long rest, preferably from a week to two or even up to a month. It is forbidden to practice physical culture and in general any kind of physical activity.
For faster rehabilitation, provide the victim.
- Long, good and sound sleep.
- Minimize work visual system. It is advisable to exclude for a while watching TV, working with a computer, tablet, phone or laptop. Reduce quantity books read or magazines.
- Use special folk compresses or ointments and gels prescribed by a doctor.
Your doctor may deem it necessary to use drug treatment.
Three bones take part in the connection of the spine with the skull: occipital bone, atlas and axial vertebra, which form two joints - atlantooccipital and atlantoaxial (Fig. 71). Both of these joints work as a functionally combined joint, providing a general movement of the head around all three axes.
The atlantooccipital joint is formed by the condyles of the occipital bone and the superior articular fossae of the atlas that articulate with them. According to the classification, this joint is simple, combined, condylar, biaxial. Movements in this joint are carried out around the frontal axis - flexion and extension of the skull (tilts of the head forward and backward) and around the sagittal axis - abduction and adduction of the skull (slight tilts of the head to the right and left).
Extra-articular features: each of the joints has a separate capsule and is externally reinforced with the following ligaments:
- anterior atlantooccipital membrane stretching between the anterior arch of the atlas and the occipital bone;
- The posterior atlantooccipital membrane, located between the posterior arch of the atlas and the posterior circumference of the foramen magnum.
The atlantoaxial joint is also combined and consists of three individual joints: median atlantoaxial and two lateral atlantoaxial joints. The median atlanto-axial joint is formed by the anterior and posterior articular surfaces of the atlas, connected to the fossa of the tooth on the anterior arch of the atlas, as well as the transverse ligament of the atlas, stretched between the two lateral masses of the atlas. According to the classification, this joint is cylindrical, uniaxial. Movements - vertical axis (turns of the head to the right and to the left). The atlas turns around the tooth by 30-40° in each direction.
The lateral atlantoaxial joint (right and left) is formed by the lower articular surface of the atlas and the upper articular surface of the axial vertebra. According to the classification, this joint is flat, multiaxial. Movement - sliding of planes relative to each other (participates in the rotation of the skull when the atlas moves around the tooth).
Extra-articular features of the atlanto-axial joint: the median and both lateral joints have separate capsules and are reinforced with a complex ligamentous apparatus. The cruciate ligament holds the tooth of the axial vertebra during its rotation around the atlas. It consists of the transverse ligament of the atlas already mentioned above and two bundles (upper and lower), respectively, going up to the anterior circumference of the foramen magnum and down to rear surface body of the axial vertebra. The cruciate ligament keeps the tooth from dislocating, which can damage the spinal cord.
Pterygoid ligaments rising to the right and left of the lateral surfaces of the tooth to the occipital bone. Ligament of the apex of the tooth, running from the apex of the tooth to the occipital bone.
In general, movements in the atlanto-axial and atlanto-occipital joints are carried out around all three axes. Rotation of the head to the right and left around the vertical axis, forward and backward tilts of the head around the frontal axis, and slight tilts of the head to the right and left around the sagittal axis.
Vertebral column as a whole. The spinal column (spine) is formed by successively overlapping vertebrae, which are interconnected by means of intervertebral symphyses, ligaments and inactive joints.
Forming the axial skeleton, the spinal column performs the following functions:
- supporting, being a flexible axis of the body;
- participates in education rear wall chest and abdominal cavity and pelvic cavity
- protective, being a receptacle for spinal cord which is located in the spinal canal.
The force of gravity perceived by the spinal column increases from top to bottom, so the size of the vertebrae also increases from top to bottom. There are five sections of the spinal column: cervical, thoracic, lumbar, sacral and coccygeal. Only the sacral section is motionless, the rest of the spine have varying degrees of mobility.
The length of the spinal column in an adult male ranges from 60 to 75 cm, in a woman - from 60 to 65 cm. This is approximately two-fifths of the length of an adult's body.
The spinal column does not occupy a strictly vertical position. It has curves in the sagittal plane. There are the following physiological curves observed in healthy person: cervical and lumbar lordosis (facing the bulge forward), as well as the thoracic and sacral kyphosis(facing the bulge back). These curves are important physiological significance, providing the most favorable depreciation conditions for the head, as well as for balancing the head with minimal muscle expenditure (cervical lordosis) and for maintaining a straightened body position (lumbar lordosis).
