ANATOMY. 



THE CIRCUMFERENCE is partly serrated for articulation with the temporal and 

 frontal bones, and partly smooth for the anterior margin of the foramen 

 lacerum medium and the inferior margin of the sphenoidal fissure, which 

 margins it assists in forming. 



Describe the Lesser Wings 1 of the Sphenoid. Called also the Pro- 

 cesses of Ingrassias,* they terminate internally in the Anterior Clinoid Pro- 

 cesses / 6 their anterior borders articulate with the orbital plate of the frontal 

 none, the posterior are free, dividing the anterior cerebral fossa from the 

 middle. Connected intimately with each of these wings are the 



Optic Foramen? formed by the separation of its roots, and transmitting the 



optic nerve and the ophthalmic artery. 



Sphenoidal Fissure? or foramen lacerum anterius,^ is bounded above by 

 the lesser wing, below by the greater wing, and transmits the 3d, 4th, 

 ophthalmic division of the 5th, and the 6th nerves, the ophthalmic vein, 

 branches of the lachrymal and middle meningeal arteries, some filaments 

 of the sympathetic nerve, and a process of the dura mater. 

 Describe the Pterygoid Processes of the Sphenoid. The wing-like 

 processes descend, I on each side of the body, and divide each into 2 thin, 

 bony plates/w connected together anteriorly, and presenting 



Pterygoid Fossa, between the plates posteriorly, the origin of the external 



pterygoid muscle. 

 Scaphoid Fossa, at the base of the internal plate, serves as the origin of the 



tensor palati muscle. 

 Hamular Process, a hook-like projection at the apex of the internal plate, 



around which plays the tendon of the tensor palati muscle. 

 Vidian Canal?* at the root of the process, for the Vidian nerve and vessels, 

 Triangular Notch, at the end of the process, articulates with the pterygoid 



process of the palate bone. 



With what bones does the Sphenoid articulate? With 12, the other 

 7 bones of the cranium and 5 of the face, the vomer, 2 malar, and 2 

 palate. 



How is the Sphenoid developed ? By 10 centres, as follows. 2 for the 

 greater wings, 2 for the lesser wings and anterior part of the body, 2 for the 

 posterior part of the body, 2 for the pterygoid processes, and 2 for the sphe- 

 noidal turbinated processes. Ossification begins in the 2d foetal month, and is 

 completed about the nth year, by the union of the turbinated processes with 

 the body. 



What muscles are attached to the Sphenoid bone? There are 12 

 pairs, as follows, viz. 



Orbital muscles , 6 all except the inferior oblique of the eye. 



