The dorsum sellae, also known as the posterior clinoid process or the dorsum of the sella turcica, is a small bony prominence located on the posterior surface of the sphenoid bone in the human skull. It serves as an attachment site for several important muscles and ligaments, and plays a vital role in the movements and stability of the head and neck.
Structure
The dorsum sellae is a small, triangular-shaped projection of bone that extends posteriorly from the sella turcica, a depression in the sphenoid bone that contains the pituitary gland. It is located at the posterior border of the sella turcica, and is separated from the rest of the sphenoid bone by a small gap known as the suprasellar cistern.
It is made up of two small plates of bone that are fused together along their midline, forming a thin and curved structure. Each plate is thin and triangular in shape, and is composed of spongy bone covered by a thin layer of compact bone. The surface of the dorsum sellae is smooth and concave, and is marked by several small grooves and depressions that provide attachment sites for muscles and ligaments.
Location
The dorsum sellae is located on the posterior surface of the sphenoid bone, which is situated in the middle of the base of the skull. It is located just above the foramen magnum, the large opening in the base of the skull through which the spinal cord passes, and just below the occipital bone, which forms the back of the skull.
It is located in close proximity to several important structures in the head and neck, including the pituitary gland, the optic chiasm, the basilar artery, and the cranial nerves. It is also located near the sella turcica, a depression in the sphenoid bone that contains the pituitary gland.
Function
The dorsum sellae serves several important functions in the head and neck. It serves as an attachment site for several muscles and ligaments, including the rectus capitis posterior major and minor muscles, the obliquus capitis inferior muscle, and the ligamentum nuchae. These muscles and ligaments help to stabilize the head and neck, and allow for a range of movements, including rotation and extension.
In addition to its role in head and neck movements, the dorsum sellae also plays a vital role in the blood supply to the brain. The basilar artery, a large blood vessel that supplies blood to the brainstem and cerebellum, passes over the dorsum sellae on its way to the brain. The close proximity of the basilar artery to the dorsum sellae ensures that the brain receives a constant supply of oxygenated blood.
Clinical Significance
There are several conditions and injuries that can affect the dorsum sellae and the surrounding structures in the head and neck. One such condition is pituitary gland tumors, which can occur when abnormal cells grow within the pituitary gland, located within the sella turcica. Pituitary gland tumors can cause a range of symptoms, including headaches, visual disturbances, and hormone imbalances, and may require surgical treatment.
In addition, the dorsum sellae and the surrounding structures in the head and neck may be injured in car accidents, falls, or other types of trauma. Such injuries can cause damage to the bones and surrounding tissues, and may result in symptoms such as neck pain, headaches, and difficulty moving the head or neck. In severe cases, these injuries may require surgical intervention to repair any damage and alleviate symptoms.
Other conditions that may affect the dorsum sellae and the surrounding structures include inflammation of the meninges (the membranes that cover the brain and spinal cord), known as meningitis, and inflammation of the brain tissue itself, known as encephalitis. These conditions can cause a range of symptoms, including headache, fever, and altered mental status, and may require treatment with medications and other therapies.
In addition to these conditions, the dorsum sellae and the surrounding structures may also be involved in surgeries related to the pituitary gland or the blood vessels of the head and neck. For example, surgery may be necessary to remove a pituitary gland tumor or to repair damage to the basilar artery. These surgeries can be complex and may carry risks, such as infection or bleeding, but may be necessary to improve the patient’s quality of life.
