OS SPHENOIDES. 81 



part of the cavity of the nose ; the posterior surface is articu- 

 lated with the cuneiform process of the occipital bone ; and 

 laterally it is extended into the great wings, or temporal processes. 

 On the upper surface of the body, the lesser wings^br the 

 apophyses of Ingrassias,* project from the lateral and anterior 

 parts ; these wings consist of two triangular plates, each of 

 Fig. 18.f which is joined to the 



other by its base, and 

 to the body of the os 

 sphenoides by its un- 

 der surface near the 

 base, and terminates 

 in a point ; their direc- 

 tion is forwards and 

 outwards, and their flat 

 surfaces are horizontal. Anteriorly they are connected by 

 suture to the ethmoid and frontal bones ; their posterior edge 

 is rounded, and detached from any other bone, forming the 

 upper margin of the foramen lacerum of the orbit of the eye ; 

 this edge is thick and prominent at its internal extremity, and 

 these prominences are called the anterior or clinoid processes ; 



* A physician of Palermo, who died in 1580, aged 70. H. 



f The superior or cerebral surface of the sphenoid bone. 1. The processus 

 olivaris. 2. The ethmoidal spine. 3. The lesser wing of the left side. 4. The 

 cerebral surface of the greater wing of the same side. 5. The spinous process. 

 6. The extremity of the pterygoid process of the same side, projecting down- 

 wards from the under surface of the body of the bone. 7. The foramen opticum. 

 8. The anterior clinoid process. 9. The groove by the side of the Sella Turcica, 

 for lodging the internal carotid artery, cavernous plexus, cavernous sinus, and 

 orbital nerves. 10. The Sella Turcica. 11. The posterior boundary of the Sella 

 Turcica ; its projecting angles are the posterior clinoid processes. 12. The 

 basilar portion of the bone. 13. Part of the sphenoidal fissure. 14. The foramen 

 rotundum. 15. The foramen ovale. 16. The foramen spinosum. 17. The 

 angular interval which receives the apex of the petrous portion of the temporal 

 bone. The posterior extremity of the Vidian canal terminates at this angle. 

 18. The spine of the spinous process ; it affords attachment to the internal lateral 

 ligament of the lower jaw. 19. The border of the greater wing and spinous 

 process which articulates with the anterior part of the squamous portion of the 

 temporal bone. 20. The internal border of the spinous process, which assists 

 in the formation of the foramen lacerum basis cranii. 21. That portion of the 

 greater ala which articulates with the anterior inferior angle of the parietal bone. 

 22. The portion of the greater ala which articulates with the orbital process of 

 the frontal bone. 



