THE GLUTEAL REGION 413 



adductor canal following stab wounds or in cases of popliteal 

 aneurism. The incision is made in the line of the vessel, and 

 as it is deepened through the superficial fascia, the great saphen- 

 ous vein or one of its tributaries may require to be retracted. 

 The deep fascia over the sartorius is very thin, and when it has 

 been divided the muscle may be recognised by the direction of 

 its fibres. After the sartorius has been retracted medially the 

 strong fascial roof of the canal is incised, and the femoral artery 

 is exposed with the saphenous nerve on its anterior surface. 

 The femoral vein lies posterior to the artery in the proximal 

 part of the canal, but distally it inclines to the lateral side. 

 In passing the aneurism needle care must be taken to avoid 

 injuring the vein. 



After ligature of the femoral artery in the adductor canal, 

 the collateral circulation is re-established (i) through the ana- 

 stomosis between the descending branch of the lateral circumflex 

 (p. 409) and the arteria genu suprema (anastomotica magna), 

 and (2) through the anastomosis between the fourth perforating 

 artery (p. 410) and branches of the popliteal (p. 445). 



The arteria genu suprema arises from the femoral just before 

 it leaves the adductor canal. It divides into a saphenous 

 branch, which becomes superficial, and an articular branch. 

 The latter enters the vastus medialis and descends on the femur 

 to take part in the anastomosis around the knee-joint (p. 445). 



THE GLUTEAL REGION. 



Bony Landmarks. The ischial tuberosity lies vertically 

 below the posterior superior iliac spine. It is deeply situated 

 under cover of the glutseus maximus when the thigh is extended ; 

 and when the thigh is flexed, although the muscle slips over the 

 tuberosity, the skin and fascise are no longer relaxed, so that 

 the recognition of this bony point becomes more difficult. 



The greater trochanter of the femur lies a hand - breadth 

 below the tubercle on the iliac crest (p. 237). In a normal 

 subject its position is indicated by a flattened depression on 

 the lateral aspect of the proximal part of the thigh, but in wasted 

 subjects it becomes a very prominent projection. Its lateral 

 aspect is about two inches long by i| inches wide, and its margins, 

 more especially the posterior, can readily be felt when the deep 



