Latticed bone of the skull. Paired and unpaired bones of the skull

The paired and unpaired bones of the skull form the skeleton of the head. Some elements have a spongy structure, others - mixed and flat. Next, consider what the skull consists of. The name of the bones, their location will also be described in the article.

General information

There are two departments in the skull. They are different in their functions and development. The skull bones of the child have their own characteristics. The brain department forms a cavity for the brain and for a number of sense organs. In it are the bones of the cranial vault and its base. In the second (facial) department are located almost all the senses. There are also initial segments of the digestive and respiratory systems.

Brain department

It has eight bones. Two of them are paired. These are temporal and parietal elements. The rest of the bones are unpaired. The brain department has some features. The bones of the cranial vault are represented by the outer and inner plates of the compact substance and the spongy structure located between them. The latter is called "diploe". This substance permeates channels in which diplic veins are present.

The outer plate has a smooth surface. It is covered with the periosteum. The eponymous segment of the inner plate is represented by a hard shell of the brain. It is thin and includes a large number of organic and inorganic compounds. In this regard, this element is fragile and brittle. In craniocerebral trauma, fracture occurs more often than damage to the outer plate.

The pomegranate has a strong fusion with the bones in the seam areas. On the rest of its length the connection is rather loose. The pustule restricts the cellular space within the boundaries of one bone. In this area, formation of hematomas and abscesses is likely.

Inner surface of the medulla

It has depressions and elevations. They correspond to the furrows and gyrus of the brain. Here, the areas of fit of the sinuses and vessels of the hard shell are also distinguished. In some areas, there are holes in the skull. They are designed for emissary veins that connect the venous sinuses of the membrane, outer and diploid vessels. The largest holes are mastoid and parietal. Some segments, for example the frontal bone of the skull, contain cavities. They are lined with mucous and filled with air. The same structure is characteristic for the latticed, temporal and sphenoid bones, as well as for the upper jaw. These elements are called airborne.

The skull of the skull

It participates in the formation of the roof and the base, the surfaces of the nasal cavity and the orbit. In adults, this is the unpaired bone of the skull. In it, scales and nose are distinguished. It also includes an ophthalmic department. Lateral in the lower parts of the bone there are elongated cheekbones. Up from each of them lies the temporal line. It delimits the surface of the temple from the front side of the frontal scales. The appendages from the segment are connected with similar ones, which depart from the cheekbones.

Scales

This is the largest piece of bone. Scales formed from two halves. The parts are connected by the frontal suture. By the age of five, he, as a rule, overgrows. In some cases, the seam remains, and the frontal segment remains divided. Scales distinguish between the outer and inner surfaces. The first one is smooth and has a convex shape. On either side of the seam, a frontal hillock (paired) is seen. Beneath it is located on both sides of the roller, which has a semilunar shape (superciliary arc). Its shape and magnitude depend on the individual features of the structure of the skeleton of the head. Between the brow ridges and hillocks a smooth surface is formed - glabella.

The outer side of the scales is separated from the orbit by the supraorbital margin (paired). Around its center there is a tenderloin. Inside it is a frontal recess. In some cases, this notch is inserted into the hole. Through it lie the nerve and blood vessels. The inside of the scales is concave. On the surface there are arterial furrows, in the center there is a crest. Impressions of convolutions are also observed here. The frontal ridge passes into the furrow of the sagittal upper sinus. At the beginning of the elevation from below there is a blind hole. On the sides of the furrow there are pits of granulations from the arachnoid shell.

Glazed department

It is represented by a bone plate of quadrangular irregular shape. In it, the lower (ophthalmic) and upper (cerebral) surfaces are distinguished. The first - smooth - is oriented in the eye socket. In its anterolateral area is a dimple of the lacrimal gland, medially and in the front - a block depression. The cerebral part, directed into the cranial cavity, contains depressions of the gyri and elevations between them.

Bow Section

This part is located between the orbital zones. It is represented by an osseous portion that delimits, on the sides and in front, a trellis notch. The lateral and posterior margins articulate with the edge of the plate, and the front side with the nasal elements and the maxillary process. In this place lies a sharp spine - the nose of the nose. It participates in the formation of the septum. In the rear sections of the nose are cells. They come in contact with similar holes in the trellis. As a result, their roof is formed.

On each side between the edge on the trellis and the nasal awn, there is aperture of the sinus. It leads to the left and right half of the hole. In adults, the size of the sinus is different. It is lined with mucous membranes. The frontal sinus opens into the middle nasal passage.

Ossification

Development of the frontal bone comes from two centers. They are formed by the end of the second month of the prenatal period near the supraorbital margin. The frontal bone of the newborn includes two separate elements. They are connected to the second year of the postpartum period. Up to five years, the seam between the halves is usually noticeable.

Cranial bone of the skull

It consists of two plates. One is horizontal, the other is perpendicular. Also this unpaired bone of the skull includes a labyrinth. This formation is represented by air-bearing cells. The labyrinth is a paired segment. The cells on each side adjoin the plate and communicate with each other, as well as with the nasal cavity. The cranial bone of the skull is in the tenderloin. Element plate refers to the brain department. The remaining parts, of which the cranial cranial bone consists, participate in the formation of the medial sides of the orbit and the walls of the nasal cavity.

The horizontal plate at the rear is articulated with a wedge-shaped element. In front and sides it is attached to the frontal bone. There are many holes in the plate. They are designed to pass the processes of the olfactory nerves. On the central line from the plate upwards there is a so-called cock's comb. The front end of the cerebral crescent is attached to it. In front of the ridge lies a twin process - the wing. The perpendicular plate has a hexagonal irregular shape. It forms the anterior part of the septum of the nose.

Labyrinth

Its cells are divided into three groups. They are separated from each other, but not clearly. Allocate the posterior, anterior and middle groups. On the lateral side they are covered by a thin orbital plate. It is oriented in the cavity of the orbit by its free surface. From the inside only a small part of the cells is covered with bone plates. Most of them remain open. They are covered by adjacent frontal, palatal, tear and sphenoid bones, as well as the upper jaw.

The medial side of the labyrinth limits the upper region of the nasal cavity. It has two thin plates - shells (middle and upper). Also there is a hook-shaped process. Between the shells there is a gap - this is the upper nasal passage. Behind and slightly above the upper depression, in some cases, there is one more - the highest. The shells, which include the cranial cranial bone, vary in shape and size, determining the different length and depth of the corresponding nasal passages.

The roof of the skeleton of the head

The cranial arch in the anterior part has a frontal bulge. There are elevations on it: the superciliary arches and the hillock. Behind the roof forms the scales of the occipital bone. On the sides of it close parietal elements. From the zygomatic process in the frontal bone along the roof is the temporal arcuate line. From above it borders a hole, which, in turn, is separated by a rolling comb from the same groove.

Connecting Elements

The bones of the skull are articulated (the table below, briefly shows the types of attachment) continuously for the most part. The main types of contiguity are synchondrosis and syndesmosis. The lower jaw is attached to the temporomandibular joint, and the sublingual element is attached to the muscle fibers. Syndesmosis is a fibrous joint in the form of a variety of sutures. As a rule, their names are formed according to the bones being joined. However, there are also such seams that have their own names. For example, the articulation of parietal bones is carried out through the sagittal, parietal and frontal - coronal suture and so on.

Synchondroses are represented as cartilage compounds. They are found mainly on the cranium. Syndetic noses of newborns are represented by connective tissue membranes. They are called fontanel.