ABSTRACT

The pituitary gland is divided into two lobes: anterior (developed from Rathke's pouch) and posterior (developed as a diverticulum growing downward from the base of the hypothalamus). It weighs less than a gram and sits in the sella turcica which is surrounded by bony walls and floor and a roof made up of dura and then the optic chiasma, hypothalamus, and third ventricle. The optic chiasma may be anterior (15%), above (80%), or behind the sella (5%). Laterally on each side is the cavernous sinus, internal carotid artery, and cranial nerves III, IV, V1, V2, and VI.