236 INFERIOR EXTREMITY 



rounded surface. In thin subjects indications of the bellies 

 of the hamstring muscles may be seen. 



Reflection of Skin. Before beginning the dissection a good-sized block 

 should be placed under the knee so as to support the limb and render the 

 muscles which bound the fossa tense. Incisions (i) a vertical incision 

 along the medial line of the limb, beginning about five inches proximal to, 

 and terminating about four inches distal to, the bend of the knee ; (2) a 

 transverse incision at the proximal end of the vertical incision ; (3) a 

 transverse incision at the distal extremity of the vertical incision. The two 

 transverse incisions should extend almost half-way round the limb. 



Two flaps of skin are thus mapped out, and these must be raised and 

 thrown, the one medially and the other laterally. 



Superficial Fascia Vena Saphena Parva (O.T. External 

 Saphenous Vein) Branches of the Posterior Cutaneous 

 Nerve of the Thigh (O.T. Small Sciatic). The fatty layer 

 upon which the skin rests is now brought into view, and the 

 cutaneous nerves and vessels must be secured. First look 

 for a small nerve a branch of the posterior cutaneous nerve of 

 the thigh -which passes distally over the space near the 

 middle line, and, when this is found, dissect out the small 

 saphenous vein. The vein ascends in the middle line of the 

 leg, and when traced proximally it will be found to disappear 

 from view by piercing the deep fascia, and entering the lower 

 part of the popliteal fossa. The terminal branch of the 

 posterior cutaneous nerve of the thigh pierces the popliteal fascia 

 at the lower part of the fossa, where it will be seen lying 

 close to the small saphenous vein. 



In removing the superficial fascia care must be taken of the deep 

 popliteal fascia, which is somewhat thin. 



Fascia Poplitea (Popliteal Fascia). Although thin, the 

 deep fascia possesses considerable strength owing to the 

 transverse fibres which are interwoven amidst its proper 

 aponeurotic fibres. In removing this fascia the dissector 

 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 opening up the fossa poplitea the dissector is recommended to 

 read the two following paragraphs, which deal generally with its contents 

 and boundaries. 



Contents of the Fossa. The principal objects within the 

 fossa poplitea are the popliteal artery and vein, with their 

 branches and tributaries, and the tibial and common peroneal 



