DISSECTING MANUAL. 



grooved. The external border of the facet is the base of the 

 triangular facet enclosed by the splitting of the interosseous 

 ridge; at its ends are tubercles. Internally a process (internal 

 malleolus) projects downward and is pointed inferiorly in front 

 but notched behind; its inner surface is convex and subcu- 

 taneous ; its outer surface has a pyrif orm facet continuous with 

 the saddle-shaped facet. A broad groove descends obliquely 

 along the posterior border of the malleolus, with a smaller one 

 just external to it. [234] 



Fibula. The upper extremity (head) is expanded, and bev- 

 elled on its inner surface. A pointed eminence (styloid process) 

 projects upward from the summit of its upper edge, and just 

 internal to this, at the top of the internal surface, is a triangular 

 facet for the tibia. There are usually tubercles in front of and 

 behind the head. Below the head is a constricted portion 

 (neck). [235] 



Shaft. The anterior border descends from the front of the 

 head and splits, enclosing a triangular subcutaneous area just 

 above the malleolus. The interosseous border, or ridge, lies 

 just internal to the preceding, being separated from it by a con- 

 siderable interval below but often fused with it above. The 

 posterior border descends from the base of the styloid process 

 and ends just above the pit on the inner surface of the lower 

 extremity. The flexor surface lies between the interosseous 

 and anterior borders. The outer (peroneal) surface lies be- 

 tween the anterior and posterior borders; it looks forward 

 above, but twists backward below where it is continuous with 

 the groove on the back of the malleolus. The extensor surface, 

 looking backward above and inward below, lies between the 

 posterior and interosseous borders; it is crossed by a curved 

 ridge (so called " internal border ") which begins below at the 

 junction of the middle and lower thirds of the interosseous 

 ridge and ascends, inclining at first backward and then for- 

 ward, to join the interosseous ridge on the neck (marking off 

 the " internal surface ") . [236] 



[254] 



