THE BRAIN

The Skull Base

The skull base is a complex and irregular surface of bone on which the brain rests. Contained within the skull base are the eye orbits, ear canals, two carotid arteries, two vertebral arteries, 12 cranial nerves and the venous system (the veins) of the brain.

The skull base is made up of three basic anatomical regions, the anterior (front) fossa, the middle fossa and the posterior (back) fossa. The anterior compartment is the region above a person's eyes. The middle compartment is the region behind the eyes and is centred around the pituitary gland. The posterior compartment houses the brainstem and cerebellum. The brainstem connects the brain and spinal cord, and contains the origin of nerves involved in the control of breathing, blood pressure, eye movements, swallowing, etc. This connection occurs through the large hole, known as the foramen magnum. The cerebellum, which lies above the foramen magnum, is involved with coordination and balance. The roof of the skull base is composed of the brain itself and an area of dura, called the tentorium, on which the brain rests.