Skulls

Skull refers to the bony framework of the head. In humans it comprises 22 bones: eight cranial bones forming the braincase and fourteen facial bones forming the face. The mandible is the only movable bone in the skull. The skull also contains the orbits, nasal cavities, and the structures that support the teeth and sense organs.

The skull’s primary functions are protection and support. The cranium safeguards the brain and houses the sensory organs for sight, hearing, balance, smell, and taste. The facial skeleton shapes the face, forms openings for the airway and digestion, and provides attachment points for muscles involved in chewing and facial expression.

Development and growth occur through the life course. At birth, skull bones are joined by sutures and fontanelles, which allow for brain growth and passage through the birth canal. With age, sutures gradually fuse as head shape becomes more fixed.

Variation and study are notable features of skulls. Skull shape varies among individuals and populations; measurements such as the cranial index describe form and are used in anthropology and forensic science. Skulls are central to paleontological and forensic analyses, providing information about age, sex estimation, and membership in a population, as well as evolutionary relationships.

Clinical and evolutionary context includes injuries, congenital conditions like craniosynostosis (premature suture fusion causing abnormal head shape), and the skull’s importance in tracing human evolution. Fossil skulls contribute to understanding brain size, diet, and phylogenetic relationships across primates and other vertebrates.