The human skull is the skeletal structure that supports the structures of the head and forms a cavity for the brain. It has 22 bones, all joined together by fairly rigid, ossified joints called sutures. The skull is divided into two regions with different embryological origins: the neurocranium and the viscerocranium.
Skull parts name:
The upper portion of the skull, called the calvaria or forehead bone, protects the cerebral cortex and cerebellum and their surrounding structures. It consists of the frontal bone superiorly, parietal bone posteriorly, and squamous part of the temporal bone inferolaterally. The posterior portion of the squamous part of the temporal bones articulates with the occipital bone centrally at the pterion. Two suture lines run across the top of the skull: the coronal and sagittal sutures.
These bone parts form a vault around the brain, known as the neurocranium. There are a few openings in this part of the skull that allow passage for blood vessels and cranial nerves.
There are also several air-filled cavities within the skull, called sinuses. They may have a variety of functions, including lessening skull weight, contributing to voice resonance and warming and moistening inspired air. The nasal cavity is occupied by the ethmoid and vomer bones, which are separated by the nasal septum. Each lateral wall of the nasal cavity contains an inferior nasal concha, which is a flat bone plate projecting from each lateral surface of the ethmoid bone. The inferior nasal concha is connected to the nasal septum by a bone called the ossiculum.
The middle cranial fossa is formed by the frontal, parietal, and temporal bones. Its occipital ridge is an important midline landmark. Two openings in the occipital ridge are the foramen ovale and the foramen spinosum. The foramen ovale allows passage for a large nerve that provides sensory information from the coverings of the brain. The foramen spinosum is an entrance point for a vein that supplies the coverings of the brain and cerebellum.
In the lower part of the skull are the temporomandibular joint (TMJ), the jawbone, and other associated structures. The skull contains two bony plates that articulate with the TMJ, namely the articular tubercle and the styloid process of the mandible.
The skull is further shaped by other bones in the facial skeleton, which includes the jawbones and other bones of the face. There are three ear bones on each side of the skull, and they include the malleus (hammer), incus (anvil), and stapes (stirrup). These ear bones are associated with the auditory system and assist in hearing, balance, and other processes. The hyoid bone is a separate bone, shaped like a U, that is associated with the tongue and helps with swallowing. There are also the teeth and other bones that make up the mouth. There are 28 bones in the skull and facial skeleton, including the mandible. The skull is a relatively rigid and protective shell for the brain and other sense organs.