The occipital bone of the skull, the photo of which is presented in the article, is unpaired. It is located in the lower back of the head. This element forms part of the arch and is involved in the formation of the base. Often from schoolchildren you can hear the question: "The occipital bone of the skull is flat or tubular?" In general, all the solid elements of the head have one structure. The occipital bone, like the others, is flat. It includes several elements. Let's consider them in more detail.
The occipital bone of the skull: anatomy
This element is connected to the temporal and parietal through sutures. The occipital bone of the human skull includes 4 parts. It has cartilage and membranous origin. The occipital bone of the skull of an animal includes:
- Scale.
- Two articular condyle.
- Body.
- Two jugular processes.
Between these parts there is a large hole. Through it, a message occurs between the brain cavity and the spinal canal. The occipital bone of the human skull is articulated with a wedge-shaped element and the 1st cervical vertebra. It includes:
- Scale.
- Condyles (lateral masses).
- Body (basilar part).
Between them is also a large hole. The cranial cavity connects to the spinal canal.
Scales
It is a spherical plate. Its outer surface is convex, and the inner one is concave. Considering the structure of the occipital bone of the skull, one should study the structure of the plate. On its outer surface there are:
- The protrusion (inion). It is presented in the form of elevation in the center of the scales. On palpation, it is palpated quite well.
- Occipital area. It is represented by a patch of scales over a ledge.
- High top line. It starts from the upper boundary of the inion.
- High top line. It runs at the level of the protrusion between the lower and highest edges.
- Bottom line. It passes between the upper edge and the occipital foramen.
Inner surface
On it are present:
- Cruciform elevation. It is located at the intersection of the internal crest and furrows of the transverse and superior sagittal sinuses.
- Inner ledge. It is located at the junction of the venous sinuses.
- Inner crest.
- Furrows: one sagittal and two transverse sinuses.
- Opistion. This is an identification point. It corresponds to the center of the posterior margin of the occipital foramen.
- Basion. This is a conditional stitch that corresponds to the center of the front edge of the occipital foramen.
The inner surface of the scales has a relief, which is determined by the shape of the brain and the shells adjacent to it.
Lateral masses
They include:
- Jugular processes. They limit the hole of the same name on the sides. These elements correspond to the transverse vertebral processes.
- Sublingual canal. It is located on the side and front of the occipital foramen. It contains the XII nerve.
- Condylar canal located behind the condyle. An emissary vein is present in it.
- Jugular tubercle. It is located above the canal of the hyoid nerve.
Body
It represents the very front part. Above and front, the body is beveled. It distinguishes between:
- Bottom surface. There is a pharyngeal tubercle, a site of accession of the pharyngeal suture.
- Two outer lines (edges). They are connected to the pyramids of the temporal element.
- Slope (upper surface). It is directed into the cranial cavity.
In the lateral part, a groove of the stony lower sinus is distinguished.
Articulations
The occipital bone of the skull is connected with the elements of the arch and base. It acts as a link between the head and spine. As mentioned above, in the considered part of the head, the sphenoid element and the occipital bone of the skull are connected. Type of joint - synchondrosis. Joining is done using the front surface of the body. The occipital bone is articulated with a suture. At the junction is a conditional point. It is called a lambda. In some cases, an inter-dark bone is found here. It is formed from the upper part of the scales and is separated from it by means of a transverse seam. With the temporal element, the occipital bone of the skull is articulated with sutures:
- Petro-jugular. The jugular process articulates with the same notch in the temporal bone.
- Petro-basilar. The lateral part of the base is connected to the pyramid of the temporal element.
- Occipital-mastoid. The mastoid part is articulated with the posterior lower plane of the temporal element.
With Atlant, the inferior convex surface of the condyles is connected to the concave parts of the 1st vertebra of the neck. Here a joint of the form of diarthrosis is formed. It contains a capsule, synovia, cartilage.
Ligaments
They are presented in the form of membranes:
- Front. It is located between the base of the bone and the arc of Atlanta.
- The back. This ligament is stretched between the back of the first vertebra of the neck and the occipital foramen. It is included in the corresponding surface of the spinal canal.
- Lateral. This membrane connects the jugular process to the transverse vertebral.
- The coverslip. It is a continuation of the longitudinal rear membrane towards the front of the large opening. This ligament passes into the periosteum of the elements of the base of the skull.
In addition, there are:
- Pterygoid ligaments. They go to the lateral parts of the large opening.
- Tooth ligament. It passes from the process of the 2nd vertebra of the neck to the front border of the large opening.
- Superficial aponeurosis. It is attached along the top top line.
- Deep aponeurosis. It is fixed to the base of the occipital bone.
Muscle
They are attached to:
- Occipital highest line. Here, the abdomen from the cranial muscle is fixed.
- The occipital superior line. Here, the belt, sternocleidomastoid, trapezius muscles are fixed. In the same place the occipital bundle of muscles is fixed.
On the bottom line are fixed:
- Direct back small muscle of the head. It is attached to the spinous process of the 1st vertebra of the neck.
- The back is a big straight. They are fixed on the spinous process of the 2nd vertebra of the neck.
- Oblique upper muscle of the head. It is attached to the transverse process of the 2nd cervical vertebra.
Brain (hard shell) and nerves
A cerebellum design is attached to the edges of the transverse sulcus. A sickle of the brain is fixed by its back. It is fixed at the edges of the sulcus on the superior sagittal sinus. Cerebellum sickle is fixed on the occipital inner crest. Through the jugular opening there are pairs of nerves:
- Gulletopharyngeal (IX).
- Wandering (X).
- Additional (XI). Its spinal roots pass through the occipital foramen.
At the condyle level, an XII pair of nerves goes through the sublingual canal.
Injuries
The structure of the occipital bone of the skull is such that it is highly susceptible to mechanical damage. Moreover, they can be accompanied by serious, in some cases, fatal consequences. This is due to the fact that the occipital bone of the skull protects the optic nerve. And its damage can lead to a complete or partial loss of the ability to see.
Types of injuries
The following damage exists:
- Indented fracture of the occipital bone of the skull. It appears from mechanical impact with a blunt object. In such situations, usually the majority of the load is on the brain.
- Cellular damage. It represents a violation of the integrity of the element, accompanied by the formation of fragments of various sizes. This can damage the brain structure.
- Linear fracture of the occipital bone of the skull. It is also a violation of the integrity of the element. In this case, damage is often accompanied by fractures of other bones, concussion and bruising of the brain. Such an x-ray injury appears as a thin strip. She shares the skull, namely its occipital bone.
The latter damage is characterized in that the displacement of the elements with respect to each other is not more than a centimeter. This fracture may go unnoticed and not manifest in any way. Such an injury is especially common in children during active games. If a child has a headache and nausea after a fall, consult a doctor.
A special case
The skull can get damage affecting the large occipital foramen. In this case, brain nerves will be injured. The clinical picture is characterized by bulbar symptoms. It is accompanied by disorders of the respiratory and cardiovascular systems. The consequences of such an injury are quite serious. This may be a violation of certain functions of the brain, and an osteoma of the back of the head, or even death.
TBI
There are three main types of brain damage:
- Concussion.
- Squeezing.
- Injury.
The most common signs of concussion include fainting lasting more than 30 seconds. up to half an hour. In addition, a person has nausea, vomiting, dizziness, pain in the head. Short-term memory loss, irritability to noise and light are likely. With simultaneous damage to the occipital bone and concussion, a complex of symptoms is noted. A slight bruise is manifested by loss of consciousness. It can be short (several minutes) or last several hours. Often there is paralysis of facial muscles, speech impairment. With a moderate bruise, a poor reaction of the pupils to light is noted, nystagmus occurs - involuntary twitching of the eyes. With severe damage, the victim may fall into a coma for several days. In this case, compression of the brain may also occur. This is due to the development of a hematoma. However, in some cases, squeezing can provoke swelling or bone fragments. This condition, as a rule, requires urgent surgical intervention.
Effects
Injuries to the occipital bone can cause one-sided visual-spatial agnosia. Doctors call this condition disorders of different types of perception. The victim, in particular, cannot see and understand the space to his left. In some cases, people believe that the injuries to the skull that they received do not pose a danger to them. However, for any damage, regardless of severity, you must go to the hospital. An early-onset condition that is not symptomatic can cause serious consequences.