sella turcica

The sella turcica is part of the sphenoid bone and consists of the tuberculum sellae anteriorly, the dorsum sellae posteriorly, and the hypophyseal fossa in the middle, which cradles the pituitary gland. The optic chiasm lies just superior and anterior to the sella turcica, which explains why pituitary macroadenomas (>1 cm) can cause bitemporal hemianopsia due to compression of the decussating fibers of the optic chiasm. The cavernous sinuses flank the sella turcica laterally, containing the internal carotid arteries and cranial nerves III, IV, V1, V2, and VI—large pituitary tumors can invade laterally and cause cranial nerve palsies. Clinically, an enlarged sella turcica on imaging (CT/MRI) is a classic finding suggestive of a pituitary adenoma (e.g., prolactinoma, growth hormone-secreting adenoma causing acromegaly, ACTH-secreting adenoma causing Cushing disease). An empty sella syndrome, where the sella appears empty on imaging due to herniation of the arachnoid and CSF into the sella (often with flattening of the pituitary gland), can be idiopathic or secondary to conditions like pseudotumor cerebri, prior pituitary surgery, or Sheehan syndrome (postpartum pituitary necrosis). Pituitary apoplexy, an acute hemorrhage or infarction of the pituitary gland (often within an adenoma), presents with sudden severe headache, visual disturbances, ophthalmoplegia, and can cause acute hypopituitarism—a medical emergency requiring prompt corticosteroid replacement. Craniopharyngiomas, which arise from remnants of Rathke's pouch, are also found in this region and can present with visual field defects and endocrine dysfunction, often with calcifications seen on imaging (especially in children).