POPLITEAL FOSSA 307 



Fascia Poplitea (Popliteal Fascia). Although it is thin, 

 the deep fascia of the popliteal region possesses considerable 

 strength owing to the transverse fibres which are interwoven 

 amidst its longitudinal fibres. As the dissector removes the 

 fascia he will notice that it is firmly attached on each side to 

 the tendons of the muscles which bound the fossa poplitea. 

 Proximally, it is continuous with the fascia lata of the thigh. 



Before the popliteal fascia is interfered with the dissector is recom- 

 mended to read the following two paragraphs, which deal in a general way 

 with the boundaries and contents of the popliteal fossa. 



Boundaries. The popliteal fossa is diamond - shaped. 

 Proximally and laterally it is bounded by the biceps femoris 

 muscle ; whilst proximally and medially are the semitendinosus 

 and the semimembranosus muscles^ the former lying upon the 

 posterior surface of the latter. On the medial side of the 

 knee, anterior to the semimembranosus, lie the gracilis, the 

 sartorius, and the tendon of the adductor magnus. The 

 fossa is bounded, distally, by the converging heads of 

 the gastrocnemius. In the formation of the distal and lateral 

 boundary the lateral head of the gastrocnemius is assisted 

 by the small plantaris muscle. 



Contents of the Fossa. The principal objects within the 

 popliteal fossa are the tibial and common peroneal nerves and 

 the popliteal artery and vein, with their branches and 

 tributaries, but the most superficial structure, in the proximal 

 part of the space, is the posterior cutaneous nerve of the thigh, 

 which runs along the middle line, immediately subjacent to 

 the popliteal fascia, until it pierces that fascia in the distal 

 part of the space. Separated from the posterior cutaneous 

 nerve of the thigh by a thin layer of fat is the large tibial 

 nerve. It lies superficial to the popliteal vein and artery 

 which are situated in a much deeper plane in close contact 

 with one another. The common peroneal nerve lies along 

 the upper lateral boundary of the fossa, under cover of the 

 posterior margin of the biceps femoris. Both the tibial and 

 the common peroneal nerves give off branches of which the 

 majority are easily found, but their articular twigs are delicate 

 and are easily destroyed by the dissector who does not 

 exercise sufficient care. One of the articular nerves, 

 however, is derived neither from the tibial nor the common 

 peroneal nerve, but from the deep division of the obturator 



