Sella turcica

Sella turcica
Human skull seen from side (parietal bones and temporal bones have been removed). Sella turcica shown in red.
Sella turcica and pituitary gland.
Details
Identifiers
Latin	Sella turcica
TA	A02.1.05.006
FMA	54079
Anatomical terms of bone [edit on Wikidata]

The sella turcica (Latin for Turkish seat) is a saddle-shaped depression in the body of the sphenoid bone of the human skull and of the skulls of other hominids including chimpanzees, orangutans, and gorillas. It serves as a cephalometric landmark. The seat of the saddle, the deepest part of the sella turcica known as the hypophyseal fossa, holds the pituitary gland (hypophysis).

Structure

The seat of the saddle, the deepest part of the sella turcica known as the hypophyseal fossa holds the pituitary gland (hypophysis). The sella turcica is located in the sphenoid bone behind the chiasmatic groove and the tuberculum sellae. It belongs to the middle cranial fossa.^[1] In front of the hypophyseal fossa is the tuberculum sellae.

Completing the formation of the saddle posteriorly is the dorsum sellae, which is continuous with the clivus, inferoposteriorly. The dorsum sellae is terminated laterally by the posterior clinoid processes.

Function

The sella turcica forms a bony seat for the pituitary gland.

Clinical significance

Empty sella syndrome is the condition of a shrunken or flattened pituitary gland.

Since the sella turcica forms a bony caudal border for the pituitary gland, a pituitary tumor usually extends upward in the rostral direction into the suprasellar region. This can result in compression of the optic chiasm, which lies on top of the pituitary, enveloping the pituitary stalk. Compression of the optic chiasm can lead to bitemporal hemianopsia, and, when there is no relevant trauma, this clinical finding is pathognomonic for a pituitary tumor.

Some pituitary adenomas can extend inferiorly, growing downward and invading the sphenoid bone and cavernous sinus.^[2] Adenomas greater than 10mm (macroadenomas) can cause remodeling of the underlying sphenoid bone altering the shape of the sella turcica.

Sella turcica is also usually used as a reference point with nasion to establish the base of the skull in cephalometric analysis. This is commonly done prior to orthodontic treatment.^[3]

Etymology

Sella turcica is from the Latin words sella, meaning seat, and turcica, meaning Turkish.

See also

• Sphenoidal sinuses
• Empty sella syndrome

Additional images

• 
  Human skull seen from side (parietal bones and temporal bones have been removed). Sella turcica shown in red.
• 
  Hypophysial fossa shown in red.
• 
  Sphenoid bone seen from above. Sella turcica shown in red.
• 
  Base of skull - Sella turcica, tuberculum sellae and hypophyseal fossa

References

• Marieb, Elaine Nicpon (2004). Human Anatomy & Physiology (6th ed.). Pearson Education. p. 209. ISBN 0-8053-5462-X. 

External links

Wikimedia Commons has media related to Sella turcica.

• Image at Indiana.edu