36 SPHENOID BONE. 



ophthalmic division of the fifth and the sixth nerves, and the ophthal- 

 mic vein. Behind and beneath this fissure is the foramen rotundum 

 for the superior maxillary nerve ; and still farther back, in the base of 

 the spinous process, the foramen ovate for the inferior maxillary nerve, 



Fig. 20.' 



arteria meningea parva, and nervus petrosus superficialis minor. Be- 

 hind the foramen ovale, near the apex of the spinous process, is the 

 foramen spinosum for the arteria meningea media. 



Upon the antero-inferior surface of the sphenoid is a long flattened 

 spine or crest, the superior part of which, crista sphenoidalis, articulates 

 with the central lamella of the ethmoid, while the inferior part longer 

 and sharper, the rostrum sphenoidale, is intended to be inserted into 

 the sheath formed by the upper border of the vomer. On either side 

 of the crista sphenoidalis is an irregular opening leading into the 



* 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 

 downwards from the under surface of the body of the bone. 7- The foramen 

 opticum. 8. The anterior clinoid process, p. The groove by the side of the 

 sella turcica; for lodging the internal carotid artery, cavernous plexus, ca- 

 vernus sinus, and orbital nerves. 10. The sella turcica; the two tubercles in 

 front of the figure are the middle clinoid processes. 1 1 . 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 in- 

 ternal lateral ligament of the lower jaw. 1Q. 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. 



