IMPORTANT ANATOMICAL LANDMARKS AND POINTS, 



CAPABLE OF BEING STUDIED WITHOUT DISSECTION, OR UPON 

 THE LIVING SUBJECT. 



CRANIUM. 



THE position of the lateral sinus is indicated by a, line 

 nearly horizontal, drawn from the occipital protuberance, 

 which may be felt at the back of the head, to the base of 

 the mastoid process of the temporal bone. 



The position of the longitudinal sinus is indicated by 

 a line drawn, over the vertex, from the root of the nose to 

 the occipital protuberance. 



The middle meningeal artery follows a course upward 

 from the anterior inferior angle of the parietal bone, or 

 from a point about one and a half inches behind the ex- 

 ternal angular process of the frontal bone. 



It is not usual to apply the trephine over the region 

 traversed by the lower part of the meningeal artery, or 

 over those corresponding to either of the above named 

 sinuses. 



FACE. 



The supra-orbital foramen, from which issues the supra- 

 orbital branch of the fifth nerve, is situated a little inside 

 of the union of the inner with the outer two-thirds of the 

 upper margin of the orbit. Its position may also be de- 

 termined by the pulsations of the supra-orbital branch of 

 the 'ophthalmic artery, issuing from it, and which, though 

 the vessel is of small size, may still be detected. 



The infra-orbital foramen, from which issues the infra- 

 orbital branch of the fifth nerve, is situated just above the 

 canine fossa, one-fourth of an inch below the lower edge of 

 the orbit. A vertical line dropped from this foramen would 

 fall upon the first molar tooth. 



