Sphenoid bone

Sphenoid bone

Sphenoid bone:

         This bone makes the anterior portion of the base of cranium. Its shape is like a bet with stretched feather. The main body of cube-shaped is in middle and there are two big and two small feathers of both sides and two pterygoid processes are bringing out at the lower side.

         Pterygoid processes make some portion of the walls of nasal cavity and the under surface of the body makes the roof of nasal cavity. There is a pit in the body which is called hypophyseal fossa or Sella turcica. The pituitary gland remains in this pit.

        Both small feathers make the floor of the anterior cranial fossa. There is an optic foramen on the base of each small feather through which optic nerve and ophthalmic artery gets entered into the orbit.

        Both big feathers make the most of portion of the middle cranial fossa. There is a superior orbital fissure between the big and small feathers which is situated between the anterior cranial fossa and orbit. From this fissure, three cranial nerves go through for the muscles of eyes and sensory nerves go through for cavity and forehead. There are three important foramens in the big feather. 

  • foramen rotundum
  • foramen ovale
  • foramen spinosum

         Several branches of trigeminal nerve bring out from the rotundum and foramen ovale and middle meningeal artery brings out from the foramen spinosum which goes to the lateral and roof of the cranium.