Skull bones: human anatomy

Skull, Lat. Cranium, is the skeleton of the head. He performs two major tasks. It is he who is the receptacle and protector of the brain and senses such as sight, hearing, smell, taste and balance. On it the initial links of the respiratory and digestive systems are based. As a rule, the skull bones of anatomy in Latin describes for proper perception around the world.

Structure of the skull

The skull relief is quite complicated. In the bony receptacles is not only the brain, but also a number of the main sense organs, through it through special channels and openings pass nerves and various vessels. It consists of 23 bones, 8 of which are paired and 7 are unpaired. Among them there are flat, spongy and mixed bones of the skull, the anatomy takes into account their connections, as they together create a single whole.

Anatomy of the human skull bone is divided into two groups: the brain and facial. Each has its own tasks and characteristics. The brain skull (Latin cranium celebrate) is larger in size and located above the face (cranium viscerale). Movable in the entire skull is only the lower jaw.

Consider the bones of the cerebral skull. Anatomy distinguishes the occipital, frontal, wedge-shaped, latticed, single temporal and parietal paired bones, as well as their connections.

The composition of the facial skull is distinguished by:

- the bones of the masticatory device - the lower and upper jaws, the upper part referring to the bony bones;

- bones, of which the nasal and oral cavity and orbit are composed, namely the single vomer and the hyoid and paired palatine, nasal, lacrimal, zygomatic bones and lower nasal concha.

Bonding

It is necessary to consider the skull bones and their joints. Human anatomy studies them both individually and in a complex. Most of the bones of the skull are connected immobile. The only exception is the mobile lower jaw and the sublingual bone attached to the muscles and ligaments.

The stitches connecting all the components together are very diverse. For the facial and bones of the cranial vault are characterized mainly by dentate, scaly and flat seams. At the base of the skull, the joints are often temporary or permanent cartilaginous, so-called synchondrosis. The sutures are named after the bones that they connect (stony-occipital, cuneate-frontal) or from the location and shape (lambdoid, sagittal).

Brain skull

Let us consider in more detail the bones of the cerebral skull: the skeleton and the joints of the bones. This part can be divided into two more important parts: the basis (Latin basis) and the vault (Latin calvaria), which is sometimes called the roof of the skull.

The peculiarity of the vault is that in its bones it is possible to distinguish between the inner and outer plates with the spongy substance of the diploe between them. The diploma contains many diplomatic channels with diplomatic veins. The smooth outer plate has a periosteum. The inner plate is more delicate and brittle, and the role of the periosteum is performed by the hard shell of the brain. It is worth noting that with injuries, a fracture of the inner plate can occur without damage to the outer plate.

The pustule only in the seam area has the most dense connection with the bones, and in other places the connection is more friable, therefore within the bone there is a subperiosteal space. In these places, sometimes there are hematomas or even ulcers.

In addition, the skull bones the anatomy divides into airborne and non-airborne. In the brain department, the frontal bones are referred to as the frontal, wedge-shaped, latticed, and temporal bones. They were called so for the presence of cavities filled with air and lined with a mucous membrane.

There are also holes in the skull intended for passage of the emissary veins. They connect the external veins with diplic and venous sinuses, passing in the hard shell of the brain. The largest in the cerebral cranium are the mastoid and parietal orifice.

Description of the structure of the main bones of the cerebral skull

Each bone of the skull consists of several parts, which have their own features and shape, can be supplemented with projections, processes, hills, notches, holes, furrows, sinuses and so on. Most fully represents all the bones of the anatomical atlas.

Bones of the Arch

The frontal bone (Latin os frontale) in its structure consists of the nasal and orbital part and frontal scales. Is unpaired. It forms the anterior part of the arch and participates in the formation of anterior cranial fossa and orbits.

The occipital bone (Latin os occipitale) is unpaired, located in the posterior part of the skull. It is divided into a basilar part, an occipital scales and two lateral parts. These components cover a large hole, called the occipital (Latin foramen magnum).

The dark pair bone (Latin os parientale) forms the upper skull sections in the cranial arch. Behind these paired bones along the sagittal margin connect with each other. The remaining edges are named frontal, scaly and occipital.

Bone Foundation

The temporal twin bone (lat. Os temporale) is located on the lateral wall of the base of the skull. Behind it is the occipital bone, and in front - wedge-shaped. Divide this bone into a pyramid (rocky), scaly and drum parts. It is here that the organs of balance and hearing are located.

Several vessels and cranial nerves pass through the temporal bone. A number of canals are provided for them: somnolent, facial, drum, drowsy, drum string, mastoid, musculo-tubular, internal auditory meatus, snail canal and waterway of the vestibule.

The sphenoid bone (Latin os sphenoidale) is located in the center of the base of the skull, necessary for the formation of its lateral sections, and also forms a series of pits and cavities. Is unpaired. It consists of large and small wings, body and pterygoid processes.

Latticed bone (Latin os ethmoidale) participates in the formation of the orbit and nasal cavity. It is divided into a lattice and perpendicular plate and trellised labyrinths. The fibers of the olfactory nerve go through the trellis plate. In the trellis labyrinth there are latticed cells filled with air, nasal passages pass through and outlets to the sinuses are located.

Bones of the facial skull as a whole

There are more bones in the facial skull than in the brain. Here their 15. Unpaired are the hyoid bone, the vomer, the lower jaw. The remaining bones are paired: lower nasal concha, nasal, zygomatic, lacrimal, palatine and upper jaw. Of these, only the upper jaw refers to the air-bearing bones, which have a cavity with a mucous membrane and air.

These bones generally make up the facial part. Considers the anatomy of the skull structure, the functions of not just individual bones, but their totality. In the facial skull, you can distinguish orbits, mouth and nose, where there are important organs, jaws. The walls of the cavities have openings and cracks for the passage of nerves and vessels, and also with their help the communication of the cavities occurs among themselves.

Facial skull: the most important holes

Paired eye sockets are designed for placement in their cavities of eyeballs with muscles, tear glands and other formations. Important are visual, nasolacrimal, alveolar and infraorbital canals, upper and lower orbital fissures, anterior and posterior latticed, skull-shaped and supraorbital opening.

In the nasal cavity, a pear-shaped aperture, a choana, a nasolacrimal and incisal canal, a wedge-palatal and nasal apertures and openings of the trellis plate are distinguished. In the oral cavity there is a large palatal and incisal canal, a large and small palatine opening.

Also in the structure of the facial skull, it is necessary to note the presence of nasal passages (lower, middle and upper), as well as wedge and frontal sinuses.

Description of the structure of the main facial bones

The upper jaw (lat. Maxilla) refers to the bony bones. It consists of the body and the zygomatic, frontal, palatine and alveolar processes.

The palatine bone (Latin os palatinum), being a pair, participates in the formation of the pterygo-palatine fossa, the solid palate and the orbit. It is divided into horizontal and vertical plates and three processes: wedge-shaped, ophthalmic and pyramidal.

The lower nasal concha (Latin concha nasalis inferior), in fact, is a thin plate, specially bent. It is equipped with three processes along the upper margin: lacrimal, latticed and maxillary. This is the twin bone.

The opener (Latin vomer) is the bone plate necessary for the formation of the bony nasal septum. The bone is unpaired.

The nasal bone (Latin os nasale) is necessary for the formation of the osseous back of the nose and the formation of the pear-shaped aperture. This bone refers to paired.

The cheek bone (Latin os zygomaticum) is important for strengthening the facial skull, with its help connect the temporal, frontal and maxillary bones. It's steamy. It is divided into the lateral, ophthalmic and temporal surfaces.

The lacrimal bone (Latin os lacrimale) for the medial wall of the orbit is the anterior part. This is the twin bone. It has a back lacrimal crest and a teardrop groove.

Specific facial bones

Next, consider the bones of the skull, the anatomy of which differs somewhat from all the others.

The lower jaw (Latin mandibula) is a bone unpaired. It is she who is the only bone of the skull that is mobile. It consists of three parts: the body and 2 branches.

The hyoid bone (Latin os hyoideum) is unpaired, located in the anterior part of the neck, on the one side of it is located the lower jaw, and on the other - the larynx. It is divided into an arched body and paired processes - large and small horns. To the skull this bone is attached to muscles and ligaments, and it also connects to the larynx.

Stages of development of the skull

Even if tests on the anatomy of the skull bone are considered from the point of view of an adult, it is necessary to know about the formation of the skull. Before taking its final form, the skull passes two more time stages. At first it is membranous, then cartilaginous, and only then does the bone stage begin. In this case, the stages gradually flow one into the other. All three stages pass the bones of the skull base and part of the facial, the rest of the membranous immediately become bony. In this case, the cartilaginous model may not have all the bone, but only a part of it, and the rest is formed immediately from connective tissue without cartilage.

At the beginning of the membranous stage, the end of the 2 week embryonic development is considered, and from the 2 months begins already cartilaginous. Ossification of each department occurs at different times. First, the center of ossification appears, then from this point the process spreads to the depth and the surface. For example, on 39th day of intrauterine development a center appears in the lower jaw, ossification of the occipital bone in its basilar part begins on day 65.

Final formation

In this case, the centers of ossification merge after birth, and here the skull bones of the anatomy describe already with less accuracy, since this can be purely individual. For some areas, this occurs in early childhood: a temporal one - up to a year, the occipital and lower jaw - from one year to four. Some bones, for example zygomatic, complete the process from 6 to 16 years, and sublingual - from 25 to 30 years. In connection with this development of the skull, it can be said that the newborn has a larger number of skull bones, since several such elements eventually merge into one final bone.

Some cartilaginous formations remain so forever. These include the cartilage of the septum and wings of the nose and small cartilages located at the base of the skull.