258 INFERIOR EXTREMITY 



as the " calf of the leg " is visible. This is largely due to the 

 fleshy bellies of the gastrocnemius muscle. Below the calf, 

 and immediately above the heel, the powerful tendo calcaneus 

 can be felt. In front of this tendon a slight hollow is apparent 

 on either side of the limb. 



The skin will be reflected from the dorsum of the foot 

 during the dissection of the leg, therefore the pre sent oppor- 

 tunity should be seized for studying the surface anatomy of the 

 foot. The individual tarsal bones cannot be recognised through 

 the integument which covers the dorsum of the foot ; but if 

 the foot be powerfully extended the head of the talus will 

 be brought into view in the shape of a slight prominence. 

 The margins of the foot require careful study, because it is 

 by the recognition of certain bony projections in these that 

 the surgeon is enabled to determine the point at which to 

 enter the knife when he is called upon to perform partial 

 amputation of the foot. Examine the medial margin first. 

 Begin behind at the projection formed by the processus medialis 

 of the calcaneus, and proceed anteriorly. About one inch 

 below the medial malleolus the medial edge of the sustenta- 

 culum tali may be recognised, and about one inch, or a little 

 more, anterior to this is the tubercle of the navicular. Then 

 comes the medial cuneiform bone, which is succeeded by 

 the first metatarsal bone. None of these bony points can 

 be said to form distinct prominences on the surface of a 

 well- developed foot. In order to distinguish them the medial 

 margin of the foot must be carefully palpated. On the 

 lateral margin of the foot the tuberosity on the base of the 

 fifth metatarsal bone stands out as a distinct landmark. 

 Posterior to it is the cuboid, and still more posteriorly the 

 lateral surface of the calcaneus, which is almost completely 

 subcutaneous. When present in a well-developed form the 

 peroneal tubercle on this surface may be distinguished, 

 about one inch distal and a little anterior to the lateral 

 malleolus. If the foot be strongly inverted the anterior end 

 of the calcaneus will be seen to project on the surface. 



Subdivision of the Leg into Regions. In the dissection of 

 the leg four distinct regions may be recognised, viz. : 



1. An anterior crural region, in which are placed those structures which 



lie anterior to the interosseous membrane, and between the two 

 bones of the leg. 



2. A medial crural region, corresponding to the subcutaneous or medial 



surface of the body of the tibia. 



