sellar

Sellar is an anatomical term referring to the sella turcica, a saddle-shaped depression in the body of the sphenoid bone at the base of the skull. The word derives from Latin sella, meaning chair or saddle. The sella turcica houses the pituitary gland (hypophysis) and forms part of the central skull base.

The sella turcica consists of several structural parts. Anteriorly, it is bounded by the tuberculum sellae, and posteriorly by the dorsum sellae. The shallow floor is the hypophyseal fossa, which contains the pituitary gland. The roof is formed by the diaphragma sellae, a dural membrane with a small opening for the infundibulum (pituitary stalk). Above the sella lies the optic chiasm, and laterally the cavernous sinuses housing several cranial nerves and the internal carotid arteries are in close relation to the sellar region.

Clinically, the sellar region is important because pituitary adenomas and other lesions can arise within or expand from the sella, potentially compressing the optic apparatus and causing visual field defects such as bitemporal hemianopia. Other nearby processes include craniopharyngiomas and meningiomas of surrounding areas. Diagnostic imaging, particularly MRI and CT, is used to assess sellar anatomy, pathology, and planning for procedures such as transsphenoidal surgery. Variants and conditions affecting the sellar region, such as empty sella syndrome, can alter its appearance on imaging and clinical presentation.