Overview Introduction Function to secrete oxytocin and vasopressin into systemic circulation recall that the posterior pituitary (or neurohypophysis) have their neuronal cell bodies in the hypothalamus Anatomy embryology derived from an evagination of the floor of the forming ventricular system the pituitary gland resides within the sella turcica underneath the sella turcica is the sphenoid sinus allowing a transphenoidal surgical approach to access the pituitary fossa the pituitary fossa is laterally bounded by the cavernous sinus the pituitary gland lies inferiorly to the optic chiasm pituitary tumors compressing the optic chiasm results in a bitemporal hemianopia Clinical correlate central diabetes insipidus secondary to vasopressin (ADH) deficiency and can result from neurosurgery head trauma malignancy affecting the pituitary-hypothalamic region syndrome of inappropriate ADH secondary to ADH excess and can results from meningitis head trauma pulmonary disorders (e.g., pneumonia and small cell lung cancer) medication side effects (e.g., selective-serotonin reuptake inhibitors, carbamazepine, and cyclophosphamide) ADH-secreting tumors