Pituitary disease

The pituitary gland lies within a bony depression called the sella turcica within the sphenoid bone at the base of the brain. Its small size belies its many important functions. The pituitary gland has a central role in body growth, metabolism, and reproduction functions.

Anatomy and Function

The pituitary gland consists of the anterior lobe (adenohypophysis), a pars intermedia, and the posterior lobe (neurohypophysis). The anterior lobe and pars intermedia are derived from Rathke's pouch. The anterior lobe is responsible for production and release of prolactin, adrenocorticotropin (ACTH), somatotropin (growth hormone), gonadotropin (GH), follicle stimulating hormone (FSH), luteinizing hormone (LH), and thyroid stimulating hormone (TSH). A portal-hypophysial system provides a direct vascular link between the median eminence of the hypothalamus and the anterior lobe. Releasing factors produced in the hypothalamus reach the pituitary through the portal system to direct release of the hormones.

The posterior lobe and infundibulum (pituitary stalk) are direct extensions of the hypothalamus. Vasopressin (ADH) and oxytocin are produced within neurons of the supraoptic and paraventricular nuclei and transported via axonal flow to the posterior lobe. The hormones are stored in secretory granules until their release into nearby capillaries.

The pituitary stalk transverses the suprasellar cisterns. The optic chiasm and nerves are located superior and anterior to the stalk and the supraclinoid carotid arteries are positioned laterally. The cavernous sinuses lie within the dura on either side of the pituitary gland and contain a meshwork of venous channels. The carotid arteries course through the middle of the sinuses. Cranial nerves 3 and 4 and the 1^st (ophthalmic) and 2^nd (maxillary) divisions of the 5^th nerve are within the lateral walls of the cavernous sinuses. The 6^th cranial nerve lies more medially within the sinus just below the cavernous carotid artery. The sphenoid sinus is immediately below the sella turcica