The immediate anatomical relationship of the pituitary gland with surrounding structures is seen in Fig. 5.1. The gland lies in a bony fossa, and its stalk pierces the fibrous diaphragma sellae. The lateral wall of the fossa is made up of the cavernous sinus in which lie the carotid syphon and the cranial nerves III, IV and VI. The optic chiasm is situated immediately above the pituitary fossa, anterior to the pituitary stalk. The hypothalamus lies above the pituitary stalk and extends to the lateral walls of the third ventricle. Bounded anteriorly by the anterior commissure and posteriorly by the mammillary body, it is composed of many sets of nuclei and neuronal tracts, a number of which terminate in the median eminence.
