ABSTRACT
The head and neck are the most intricate regions of the body, with many major nerves and blood vessels in close proximity to one another. In life the cranial cavity is lined by the dura mater, the outermost and toughest of the three membranes or meninges that cover the brain. The dura is firmly adherent to the periosteal lining of the cranial cavity, so there is normally no patent extradural space. The brain, consisting of the cerebrum, brainstem and cerebellum joined together by the midbrain, is the part of the central nervous system that lies within the cranial cavity of the skull. The functions of certain areas are clearly defined; among the most important are those that control the movements of skeletal muscles and those at which various kinds of sensory impressions reach consciousness. The vertebral artery enters the skull through the foramen magnum and unites with its fellow to form the single midline basilar artery.
