The skull consists of a set of bones of the head, firmly connected by seams together. An exception is the lower jaw. In the connected bones in the head are the organs of smell, hearing and vision, as well as the brain. They are also a support for the nasal cavity and the skeleton of the oral cavity. This causes the division of the skull into a section of the bones of the skull and a section of the bones of the face. The brain section consists of two paired (parietal and temporal) bones, and four unpaired (frontal, sphenoid, occipital and ethmoid) bones. The irregular shape of the skull may depend on the degree of development of the masticatory apparatus and the brain itself.
The occipital bone, which is part of the cranial bones, looks like a flat bowl. Its parts are limited by a large (occipital) opening, which performs the function of connecting the cranial cavity and spinal canal. The sphenoid bone is located between the frontal and occipital bones, which are located in the base that forms the skull. The structure of this bone includes a body, the upper surface of which is curved and has a pituitary groove, and three paired processes (large and small wings and pterygoid processes). Inside the temporal (most complex) bone is the organ of balance and hearing. A channel of the nerve of the face, carotid artery also passes through it . In addition, there are bone canals and a canal of the hearing tube (the bone part). The parietal bone looks like a quadrangular concave bone plate with serrations at the edges (except for the lower edge). Outside the surface of the skull there is a parietal tubercle. The composition of the frontal bone includes paired orbital parts, frontal scales and the nasal part. The ethmoid bone is located in the deep section forming the skull. The bone structure includes a trellis plate with a perpendicular plate extending vertically downward from it, which is part of the nasal septum structure.
The facial bones include paired bones (six in total). Here is the nasal, palatine, zygomatic, lacrimal bone, lower concha and upper jaw. Unpaired bones are also referred to the department: the opener and lower jaw. The hyoid bone is also part of the facial section that forms the skull. The structure of most bones is quite complex. They contain channels and openings with passing nerves and blood vessels. In some individual bones, there are internal sinuses (cavities, sinuses, cells) that are filled with air.
The small lacrimal bone includes a crest and a lacrimal groove. It is located on the medial orbital wall. The nose bone looks like a quadrangular plate, elongated in length. The nasal bones on the left and right form the basis of the bones of the nasal dorsum. The vomer is involved in the formation of a septum in the nasal cavity. The composition of the upper jaw includes four processes and a body consisting of four (nasal, orbital, posterior (infratemporal) and anterior) surfaces. There are two bone plates in the palatine bone. The size of the zygomatic bone affects the shape and width of the face. The lower jaw is the only moving element of all that form the skull. The structure of the jaw includes a body and paired branches extending at an obtuse angle from it.
The development of the bones of the head, as well as the bones of the limbs and trunk, begins with the stage of tissue union. As for the components of the cranial base of the bones and their parts, their development includes cartilage and bone (final) stages. The bones of the roof and face go through only two stages (bone and membranous).
Senile deformations of the skull are accompanied by resorption of ridges, spongy bone material. At the same time, it becomes fragile, due to which its weight is reduced. Changes in cranial shape can be affected by mechanical stress.