Posterior clinoid processes

Posterior Clinoid Processes

Base of the skull. Upper surface. (Posterior clinoid process labeled at center left.)

The Posterior Clinoid Processes are two small bony protrusions found at the base of the sphenoid bone in the human skull. They are part of the sella turcica, a saddle-shaped depression that houses the pituitary gland. The posterior clinoid processes serve as points of attachment for several important structures in the brain, including the tentorium cerebelli and the petrosphenoidal ligament.

Anatomy

The posterior clinoid processes are located on the upper surface of the body of the sphenoid bone, posterior to the dorsum sellae. They are paired structures, with one on each side of the midline. Each process is conical in shape and points upwards and backwards.

Sphenoid bone. Upper surface. (Posterior clinoid process labeled at center right.)

Function

The posterior clinoid processes serve as attachment points for several structures:

• The tentorium cerebelli, a fold of the dura mater that separates the cerebellum from the inferior portion of the occipital lobes.
• The petrosphenoidal ligament (Gruber's ligament), a fibrous band that extends from the tip of each posterior clinoid process to the petrous apex of the temporal bone.

Clinical Significance

Due to their location and the structures they are associated with, the posterior clinoid processes can be involved in several pathological conditions. For example, they can be eroded in cases of pituitary adenomas or other sellar region tumors. They can also be involved in basilar invagination, a condition where the top of the spinal column pushes into the base of the skull.

See Also

• Anterior clinoid process
• Sphenoid bone
• Sella turcica