Occipital bone of human and animal skull: photo and structure

The occipital bone of the skull, the photo of which is presented in the article, is unpaired. It is located in the back of the lower part of the head. This element forms part of the arch and participates in the formation of the base. Often from school children you can hear the question: "The occipital bone of the skull - flat or tubular?" In general, all solid elements of the head have one structure. The occipital bone, like the others, is flat. It includes several elements. Let us consider them in more detail.

Occipital skull: anatomy

This element is connected with the temporal and parietal by means of sutures. The occipital bone of the human skull includes 4 parts. It has a cartilaginous and membranous origin. The occipital bone of the animal's skull includes:

1. Scales.
2. Two articular condyles.
3. Body.
4. Two jugular processes.

Between these parts is a large hole. Through it there is a communication between the cerebral cavity and the vertebral canal. The occipital bone of the human skull is articulated with the wedge-shaped element and the 1st cervical vertebra. It includes:

1. Scales.
2. The condyles (lateral masses).
3. Body (basilar part).

There is also a large hole between them. The cranial cavity is connected to the vertebral canal.

Scales

It is a plate of a spherical shape. Its outer surface is convex, and the inner surface is concave. Considering the structure of the occipital bone of the skull, it is necessary to study the structure of the plate. On its outer surface there are:

1. The protuberance (inion). It is represented in the form of an eminence in the center of the scale. When palpation, it is probed well enough.
2. Occipital pad. It is represented by a patch of scales above the ledge.
3. The highest euphotic line. It starts from the upper border of the inion.
4. Oily upper line. It passes at the level of the protrusion between the lower and the highest edge.
5. Bottom line. It passes between the upper edge and the occipital opening.

Inner surface

It is attended by:

1. Crosswise elevation. It is located at the intersection of the inner crest and the furrows of the transverse and superior sagittal sinuses.
2. Inner ledge. It is located at the junction of venous sinuses.
3. The inner crest.
4. Furrows: one sagittal and two transverse sinuses.
5. Opistion. This is the identification point. It corresponds to the center of the posterior edge of the occipital orifice.
6. Bazion. This is a conventional stitch, which corresponds to the center of the anterior margin of the occipital orifice.

The internal surface of the scales has a relief, which is determined by the shape of the brain and shells adjacent to it.

Lateral masses

They include:

1. Jugular processes. They limit the same hole from the sides. These elements correspond to the transverse vertebral processes.
2. Sublingual canal. It is located on the side and in front of the occipital opening. It contains the XII nerve.
3. The condyle canal, located behind the condyle. It has an emissary vein.
4. The jugular tubercle. It is located above the canal of the hyoid nerve.

Body

It represents the very front part. The body is beveled from above and from the front. It distinguishes:

1. Lower surface. It has a pharyngeal tubercle, a site of attachment of the pharyngeal suture.
2. Two outer lines (edges). They are connected with the pyramids of the temporal element.
3. Scat (upper surface). It is directed into the cranial cavity.

In the lateral part a furrow of stony inferior sinus is distinguished.

Articulations

The occipital bone of the skull is connected to the elements of the arch and the base. It acts as a link between the head and the spine. As was said above, the wedge-shaped element and the occipital bone of the skull are connected in this part of the head. Type of joint - synchondrosis. The connection is made using the front surface of the body. With the parietal bone the occipital articulated with a suture. A conditional point is located at the junction. It is called "lambda". In some cases, an intertemporal 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 by the sutures:

1. Petro-yugular. The jugular process is articulated with the same notch in the temporal bone.
2. Petro-basilar. The lateral part of the base is connected to the pyramid of the temporal element.
3. Occipital-mastoid. The osseous part joins the posterior plane of the temporal member.

With the atlas, the lower convex surface of the condyles is connected to the concave parts of the first vertebra of the neck. Here a joint of the form of diarthrosis is formed. It contains a capsule, synovia, cartilage.

Bundles

They are presented in the form of membranes:

1. Front. It is located between the base of the bone and the arch of the atlant.
2. The rear. This ligament is stretched between the posterior parts of the first vertebra of the neck and the occipital opening. It is included in the composition of the corresponding surface of the spinal canal.
3. Lateral. This membrane connects the jugular process with the transverse vertebra.
4. Cover. It is an extension of the longitudinal posterior membrane toward the anterior part of the large opening. This ligament passes into the periosteum of the elements of the base of the skull.

In addition, there are:

1. Pterygoid ligaments. They go to the lateral parts of the large opening.
2. Bundle of tooth. It extends from the appendage of the 2nd vertebra of the neck to the anterior border of the large opening.
3. Superficial aponeurosis. It is attached on the upper fringe.
4. Deep aponeurosis. It is fixed on the base of the occipital bone.

Muscles

They are attached to:

1. The occipital highest line. Here the abdomen from the supracranial muscle is fixed.
2. The occipital upper line. Here, the belt, chest-clavicular-mastoid, trapezius muscles are fixed . In the same place, the occipital fasciculus of the musculature is also fixed.

The lower line records:

1. Straight back small head muscle. It is attached to the spinous process of the first vertebra of the neck.
2. The back is a large straight. They are fixed on the spinous process of the second vertebra of the neck.
3. Slanting upper muscle of the head. It is attached to the transverse process of the 2nd cervical vertebra.

Brain (hard shell) and nerves

The nerve of the cerebellum is attached to the edges of the transverse furrow. The croup of the brain is fixed by its back part. It is fixed on the edges of the furrow on the upper sagittal sinus. Sickle of the cerebellum is fixed on the occipital inner crest. Through the jugular hole there are pairs of nerves:

1. Glossopharyngeal (IX).
2. Wandering (X).
3. Additional (XI). Its spinal roots pass through the occipital orifice.

At the level of the condyles through the hyoid canal goes the XII pair of nerves.

Injuries

The structure of the occipital bone of the skull is such that it is highly susceptible to mechanical damage. In this case, 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

There are the following injuries:

1. Pressed fracture of the occipital bone of the skull. It appears from the mechanical impact of a blunt object. In such situations, usually the most part of the load is the brain.
2. Splinter damage. It is a violation of the integrity of the element, accompanied by the formation of fragments of different sizes. This can damage the brain structure.
3. 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 brain contusion. Such a trauma on the X-ray image looks like a thin strip. It divides the skull, namely its occipital bone.

The last damage is different in that the displacement of the elements relative to each other is no more than a centimeter. This fracture can go unnoticed and does not manifest itself in any way. Such a trauma is especially common in children during active games. If a child has a headache and nausea after a fall, it is necessary to consult a doctor.

A special case

The skull can get a lesion that affects the large occipital foramen. In this case, the brain nerves will be traumatized. The clinical picture is characterized by bulbar symptoms. It is accompanied by violations of the respiratory and cardiovascular systems. The consequences of such a trauma are serious enough. This may be a violation of certain brain functions, and osteoma of the occiput bone , and even fatal outcome.

TBI

There are three main types of brain damage:

1. Shake.
2. Squeezing.
3. Injury.

The most common signs of a state of concussion include a syncope lasting 30 seconds. Up to half an hour. In addition, a person has nausea, vomiting, dizziness, pain in the head. Probable short-term memory loss, irritability to noise and light. 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 for several hours. Often there is paralysis of facial muscles, speech disorders. In case of a moderate injury, a bad reaction of the pupils to the light is noted, nystagmus arises - involuntary twitching of the eyes. In case of severe damage, the victim may fall into a coma for several days. In this case, there may also be a squeezing of the brain. This is due to the development of the hematoma. However, in some cases, compression may provoke swelling or bone fragments. Such a condition, as a rule, requires urgent surgical intervention.

Effects

Injuries to the occipital bone can cause a one-sided visual-spatial agnosia. This condition doctors call violations of different types of perception. The victim, in particular, can not see and understand the space to his left. In some cases, people believe that the skull injuries they received do not pose a danger to them. However, for any damage, regardless of the degree of severity, it is necessary to contact the hospital. No symptoms in the early stages of the manifestation can have serious consequences.