What is the Sella Turcica
The sella turcica is a saddle-shaped bony depression on the superior surface of the sphenoid bone in the middle cranial fossa that houses and protects the pituitary gland. 1
Anatomical Structure
The sella turcica is located on the intracranial surface of the sphenoid bone and derives its name from the Latin term meaning "Turkish saddle" due to its characteristic shape 1
This bony structure was first formally designated as "sella turcica" by anatomist Adrianus Spigelius (1578-1625) in his work De Corpora Humanis Fabrica (1627), though Andreas Vesalius had earlier described it as a cavity for the gland that receives the "phlegm of the brain" in 1543 1
The structure consists of measurable dimensions including depth, length, width, volume, floor thickness, intraclinoid distance, and tuberculum sellae length, with anatomic variations that can be identified on imaging 2
Clinical Significance
The sella turcica's primary function is to contain the pituitary gland, and abnormalities in its size or structure may cause pituitary dysfunction due to changes in the pituitary gland structure or may be associated with genetic or acquired endocrine disorders 1
Empty sella occurs when the subarachnoid space herniates into the sella turcica, and approximately 30% of patients with this finding demonstrate some degree of hypopituitarism upon testing, though most remain asymptomatic 3
The sella turcica can be affected by various pathologies including tumors (craniopharyngioma, meningioma, Rathke cleft cyst), inflammatory processes (sarcoid, lymphocytic hypophysitis), and metastatic disease 4
Imaging Evaluation
MRI using high-resolution pituitary protocols is the preferred imaging modality for evaluating the sella turcica and can characterize lesions even without IV contrast, though contrast increases conspicuity of small adenomas 3, 5
CT imaging can demonstrate bone-destructive lesions affecting the sella turcica, sellar enlargement, bony erosion, and calcifications that help distinguish different pathologies 6
The sella turcica is visible on lateral cephalometric radiographs routinely conducted for orthodontic diagnosis, though modern radiological imaging techniques have largely replaced plain radiography for investigating hypothalamo-pituitary abnormalities 1, 7
Relationship to Surrounding Structures
The sella turcica is surrounded by critical neurovascular structures including the cavernous sinuses laterally, the optic chiasm superiorly, and the sphenoid sinus inferiorly 8
Pathologies affecting the sella can cause sellar expansion, suprasellar extension with compression of the optic chiasm and hypothalamus, invasion into the clivus or sphenoid sinus, and displacement or encasement of vessels in the suprasellar region 6
Proper localization of abnormalities within versus adjacent to the sella turcica is critical for separating parasellar masses (meningiomas, skull base tumors, carotid aneurysms) from true pituitary masses 8