What Is the Dorsum Sellae?

The term dorsum sellae is Latin, and it means “the back of the saddle.” The saddle refers to the part of the cranial sphenoid bone called the sella turcica, which translates to “the Turkish saddle.” The rear border of the sella turcica is the dorsum sellae, which is a plate of bone formed in a square shape. It is used as an anatomical marker for the pituitary gland, which is housed in the sella turcica.

The sphenoid is an unpaired wedge-shaped bone located in the skull's base, fronting the temporal bone. It's similar in appearance to a butterfly and helps make up the eye socket. The sphenoid bone is made up of six sections: the medial portion, which is called the body of the sphenoid bone; two greater wings; two lesser wings; and the two pterygoid processes, which are counted as one section.

The sella turcica is located in the body of the sphenoid bone, which is essentially cube-shaped and has a hollow interior with two large cavities that are separated by a septum, or a wall-like structure. The middle of the sella turcica is a depression, or fossa, called the hypophyseal fossa, which is also called the seat of the saddle. The pituitary gland sits in the hypophyseal fossa. The back of the sella turcica is a bony ridge called the dorsum sellae, and it resembles the high-backed rear support of historical Turkish and Arabic saddles. Located on the sloping backside of the dorsum sellae is a shallow depression called the clivus, which supports the upper portion of the brain stem structure known as the pons.

The front edge of the sella turcica is formed by two small bony peaks called the anterior clinoid processes, which provide attachment for a membrane of tissue called the tentorium cerebelli, which is also known as the cerebellar tentorium and is an extension of the layer of meningeal tissue called the dura mater. The dorsum sellae provides the rear boundary of the sella turcica, and it ends in two tubercles, or bumps, called the posterior clinoid processes, which are highly variable in both size and shape in different people. The posterior clinoid processes also provides attachment for the tentorium cerebelli. Some individuals also have a third projection called the middle clinoid process, which is a bony spike located behind and to the side of the sella turcica.