sella

Sella is a term rooted in Latin, meaning saddle. In anatomical usage, it most commonly refers to the sella turcica, a saddle-shaped depression in the sphenoid bone at the base of the skull. The sella turcica forms a protective enclosure for the pituitary gland, also known as the hypophysis.

Anatomically, the sella turcica has three parts: the tuberculum sellae at the front, the hypophyseal fossa (or pituitary fossa) in the center, and the dorsum sellae at the back. The roof is formed by the diaphragma sellae, a fold of meningeal tissue. The pituitary gland rests within the fossa, connected to the hypothalamus by the infundibulum. The optic chiasm sits superior to the sella, and the cavernous sinuses lie laterally. Blood supply is mainly from branches of the internal carotid arteries.

Clinical significance is mainly radiological and developmental. Variations in size, depth, or shape are common. The sella can be evaluated with computed tomography or magnetic resonance imaging. Empty sella syndrome occurs when the sella is filled with cerebrospinal fluid, and the pituitary gland appears flattened; this condition can be incidental or associated with pituitary dysfunction or intracranial hypertension. Lesions such as pituitary adenomas may expand into or compress the sella, altering its appearance on imaging.

Etymology traces to Latin sella, meaning chair or saddle. The term underscores the saddle-like geometry of this skull base structure.