POPLITEAL FOSSA 305 



In the sides of the area, about the middle of its length, 

 the condyles of the femur are easily distinguished ; distal to 

 them lie the condyles of the tibia. The head of the fibula is 

 posterior and a little distal to the most projecting part of the 

 lateral condyle of the tibia. 



The tendons which form the medial and lateral boundaries 

 of the proximal part of the popliteal fossa are the tendons of 

 the hamstring muscles ; the biceps femoris on the lateral side 

 and the semitendinosus and semimembranosus on the medial 

 side. They can be seen in both the extended and flexed 

 positions of the knee, but they are most obvious when the 

 knee is flexed. When the knee is flexed and deep pressure 

 is made in the middle of the hollow between the hamstring 

 tendons, the (injected) popliteal artery can be distinguished, 

 and in the living subject the pulsations of the artery can be 

 felt. The biceps tendon should be followed to its insertion 

 into the head of the fibula whilst the knee is flexed, then the 

 knee should be extended. When that has been done and 

 pressure is made immediately above the head of the fibula, 

 at the anterior border of the biceps tendon, the proximal 

 part of the cord-like fibular collateral ligament of the knee 

 joint may be distinguished, whilst, on the medial side of the 

 posterior border of the biceps tendon, the common peroneal 

 nerve can be felt. When a little care is exercised the nerve 

 can be rotated against the posterior part of the lateral 

 condyle of the femur, but palpation of the nerve is more 

 easily done in the living than the dead body. The nerve 

 should be followed to the back of the head of the fibula 

 where it can be pressed against the proximal part of the 

 soleus muscle. When the knee joint is extended the 

 rounded tendon of the adductor magnus can be felt, as 

 it passes to its insertion into the adductor tubercle, which lies 

 on the upper border of the medial condyle at the distal end 

 of the medial supracondylar ridge. The adductor tubercle 

 is an important practical landmark, for it indicates the plane 

 of junction of the body of the femur with the distal epiphysis. 



In muscular subjects the two heads of the gastrocnemius 

 muscle form prominent rounded cushions which extend from 

 the distal part of the popliteal area into the proximal part of 

 the posterior region of the leg. 



Proximal to the popliteal region the posterior region of the 

 thigh presents a smooth rounded surface, on which, in thin 



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