AND PHYSIOLOGY. 



45 



edge a large orifice for the 

 passage of the spinal mar- 

 row, just as it enters the 

 vertebrae. It is in the 

 most posterior part of the 

 skull, joining with the 

 sphenoid in front, and rest- 

 ing upon the Atlas verte- 

 bra. The Sphenoid Bone 

 is directly underneath the 

 skull, extending from side 

 to side, forming a very 

 small portion of the out- 

 side of the skull at the 

 point where the frontal 

 and temporal bones come 

 the nearest to each other. 

 From its name we learn 

 that it is somewhat wedge- 



Fig. 48. 



External surface of Occipital Bone. 1 and 4, 

 Semicircular Ridges. 2, Occipital Protube- 

 rance. 3, Attachment of ligamentum nuche. 

 5, Foramen for Medulla oblongata. 6, Condyle 

 of right side. 7 and 8, Condyloid Foramina. 

 9, Jugular Eminence. 10, Jugular Foramen. 

 II, Basilar process. 12, Points of attachment 

 for odontoid ligaments. 13, Edge for attach- 

 ment with Parietal bone. 14, Point of attach- 

 ment for Temporal bone. 



FIG. 49. 



The Anterior and Inferior Surface of the Sphenoid Bone. 1, 1, Apophyses of Ingras- 

 sias. 2, 2, The great Wings. 3, Ethmoidal Spine. 4, Azygos Process. 5, Sphenoidal 

 Cells, after the removal of the Pyramids of Wistar. 6, Posterior Clinoid Processes. 

 7, Sphenoidal Fissure. 8, Foramen Rotundum. 9, Depression for the Middle Lobes of 

 the Cerebrum. 10, Surface for the Temporal Muscle. 11, Styloid Process. 12, Exter- 

 nal Pterygoid Process. 13, Internal Pterygoid Process. 14, Pterygoid Foramen. 15, Ar- 

 ticular Face for the Os Frontis. 16, Points to the Sella Turcica. 



