6 LANDMARKS MEDICAL AND SURGICAL. 



corresponds with the lower level of the posterior lobe. The 

 lower level of the cerebellum cannot be defined by external 

 examination. It depends upon the extent to which the 

 occipital fossae bulge into the nape of the neck ; and this 

 bulge varies in different skulls. 



THE FACE. 



8. The approaches to the organs of the senses, their 

 ever-varying expression, their numerous muscles, and their 

 rich profusion of vessels and nerves, give the face great 

 anatomical importance, which has a most valuable bearing, 

 not only on the practice of surgery, but on the physiognomy 

 of health, and in the diagnosis of disease. 



9. Foramina for branches of fifth nerve. As a 

 surgeon may be called upon to divide any one of the three 

 chief branches of the fifth nerve upon the face, he looks with 

 interest to the precise situations where they leave their bony 

 foramina with their corresponding arteries. The supraorbital 

 notch or foramen can be felt about the junction of the inner 

 with the middle third of the supraorbital margin. From this 

 point a perpendicular line drawn with a slight inclination 

 outwards, so as to cross the interval between the two bicuspid 

 teeth in both jaws, passes over the infraorbital and the mental 

 foramina. The direction of these two lower foramina looks 

 towards the angle of the nose. 



10. Pulley for superior oblique muscle. By pressing 

 the thumb beneath the internal angular process of the frontal 

 bone, the cartilaginous pulley for the tendon of the superior 

 oblique muscle can be distinctly felt. We should be careful not 

 to interfere with this pulley in any operation about the orbit. 



1 1. Lower jaw. The working of the condyle of the jaw 

 vertically and from side to side can be distinctly felt in front 

 of the ear. When the mouth is opened wide, the condyle 

 advances out of the glenoid cavity on to the eminentia 

 articularis, and returns into its socket when the mouth is 

 shut. The muscle which causes this advance is the external 



