The skull is assembled out of 22 flat or irregularly formed single bones, the cranial bones. It is part of the human skeleton. With the exeption of the mandibula, all skull bones are rigidly connected to each other.
The exact number of cranial bones frequently varies in literature. This is also because some authors cound the hyoid bone and the auditory ossicles.
Anatomy
The skull is divided into neurocranium and facial skull (viscerocranium) with the connection between sphenoid bone and ethmoid bone marking the border.
Neurocranium
The neurocranium then divided into the base of the skull and the roof of the scull (calvaria). It consists of seven bones:
Facial skull
The viscerocranium form the bony base of the face with eye-, mouth- and nose-openings. It consists of fifteen bones:
The border between neuro- and viscerocranium is best recognizable if viewed from the side. In humans it is along the upper rim of the orbita towards the external ear opening. The viscerocranium is therefore ventrally and caudally of the neurocranium.
(Foto: Messe Duesseldorf/Constanze Tillmann)