Os sphenoidale

Os Sphenoidale is one of the bones of the human skull. It is a complex, unpaired bone situated in the middle part of the base of the skull, in front of the temporal bone and basilar part of the occipital bone. The sphenoid bone is one of the seven bones that articulate to form the orbit.

Structure

The sphenoid bone consists of a central part, the body, two greater wings, two lesser wings, and two pterygoid processes. The body is more or less cuboid, but its upper surface is curved and presents the sella turcica, a depression that houses the pituitary gland.

Development

The sphenoid bone is derived from the mesoderm layer of the embryo. It is formed by the fusion of multiple elements during fetal development. The greater and lesser wings and the pterygoid processes are formed by intramembranous ossification, while the body and the pre-sphenoid part of the bone are formed by endochondral ossification.

Function

The sphenoid bone contributes to the floor of the middle cranial fossa and the lateral wall of the skull. It also forms part of the orbit and the nasal cavity. The sphenoid bone contains several foramina through which various cranial nerves and vessels pass.

Clinical significance

Due to its location and the vital structures it houses, fractures of the sphenoid bone can have serious consequences, including damage to the cranial nerves and the pituitary gland. Conditions such as sphenoid sinusitis and sphenoid wing meningioma can also affect the sphenoid bone.

See also

• Skull
• Cranial bones
• Human skeleton