Hypophysial fossa
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The sella turcica ( Latin for 'Turkish saddle') is a saddle-shaped depression in the body of the
sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bones ...
of the human skull and of the skulls of other hominids including
chimpanzee The chimpanzee (''Pan troglodytes''), also known as simply the chimp, is a species of great ape native to the forest and savannah of tropical Africa. It has four confirmed subspecies and a fifth proposed subspecies. When its close relative th ...
s, gorillas and orangutans. It serves as a cephalometric landmark. The pituitary gland or hypophysis is located within the most inferior aspect of the sella turcica, the hypophyseal
fossa Fossa may refer to: Animals * Fossa (animal), the common name of a carnivoran mammal of genus ''Cryptoprocta'' endemic to Madagascar * ''Fossa'', the Latin genus name of the Malagasy civet, a related but smaller mammal endemic to Madagascar Pla ...
.


Structure

The sella turcica is located in the sphenoid bone behind the chiasmatic groove and the tuberculum sellae. It belongs to the middle cranial fossa. The sella turcica's most inferior portion is known as the hypophyseal fossa (the "seat of the saddle"), and contains the pituitary gland (hypophysis). 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.


Development

It is widely believed that the development of the diaphragma sellae is a factor which determines the morphology of the sella turcica and its contents.


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 Caudal may refer to: Anatomy * Caudal (anatomical term) (from Latin ''cauda''; tail), used to describe how close something is to the trailing end of an organism * Caudal artery, the portion of the dorsal aorta of a vertebrate that passes into the ...
border for the pituitary gland, a pituitary tumor usually extends upward in the
rostral Rostral may refer to: Anatomy * Rostral (anatomical term), situated toward the oral or nasal region * Rostral bone, in ceratopsian dinosaurs * Rostral organ, of certain fish * Rostral scale, in snakes and scaled reptiles Other uses * Rostral colu ...
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 Bitemporal hemianopsia, is the medical description of a type of partial blindness where vision is missing in the outer half of both the right and left visual field. It is usually associated with lesions of the optic chiasm, the area where the opt ...
, 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. Large adenomas 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.
Proffit, William R. William Robert Proffit (April 19, 1936 – September 30, 2018) was an American orthodontist. He was made a fellow of the American Association for the Advancement of Science in 1966. Proffit led the department of orthodontics at the University of N ...
Contemporary Orthodontics, 4th Edition. C.V. Mosby, 122006. 6.5.2.1). vbk:978-0-323-04046-4#outline(6.5.2.1)


Etymology

''Sella turcica'' is from the Latin words ''sella'', meaning seat, and ''turcica'', meaning
Turkish Turkish may refer to: *a Turkic language spoken by the Turks * of or about Turkey ** Turkish language *** Turkish alphabet ** Turkish people, a Turkic ethnic group and nation *** Turkish citizen, a citizen of Turkey *** Turkish communities and mi ...
.


See also

*
Sphenoidal sinuses The sphenoid sinus is a paired paranasal sinus occurring within the within the body of the sphenoid bone. It represents one pair of the four paired paranasal sinuses.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, ...
* Empty sella syndrome


Additional images

File:Sella turcica - animation03.gif, Human skull seen from side ( parietal bones and temporal bones have been removed). Sella turcica shown in red. File:Hypophysial fossa01.png, Hypophysial fossa shown in red. File:Sella turcica - animation02.gif,
Sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bones ...
seen from above. Sella turcica shown in red. File:Base of skull 8.jpg, Base of skull - Sella turcica, tuberculum sellae and hypophyseal fossa


References

*


External links


Image at Indiana.edu
{{Authority control Bones of the head and neck