408 THE INFERIOR EXTREMITY 



to its origin, for aneurism, or following wounds of the vessel, or 

 as a preliminary step to a disarticulation at the hip- joint. The 

 incision may be made in the course of the artery or at right 

 angles to it. In the latter case the lumbo-inguinal nerve (p. 

 399) is usually divided, and the femoral vein, which lies medial 

 to the artery, and the femoral nerve, which lies to its lateral side, 

 run risk of injury. When the skin and superficial fascia have 

 been divided, only the fascia lata and the anterior wall of the 

 femoral sheath, which is usually adherent to it, have to be 

 incised before the artery is exposed. 



After ligature of the femoral artery at this site, the circulation 

 is re-established (i) through the anastomosis of the deep circum- 

 flex iliac, from the external iliac, with the superficial circumflex 

 iliac and the ascending branch of the lateral circumflex ; and 

 (2) through the anastomosis in the region of the quadrate 

 tubercle (p. 419), where the gluteal branches from the hypo- 

 gastric (internal iliac) anastomose with branches which arise 

 from the femoral on the distal side of the ligature. 



Axial anastomosis of the femoral artery and vein has 

 been carried out in this situation in cases of threatened gangrene. 

 The vessels are divided and the proximal end of the artery is 

 sutured to the distal end of the vein, while the proximal end of 

 the vein is similarly sutured to the distal end of the artery. In 

 this way an endeavour is made to reverse the course of the 

 blood-stream in the lower limb. 



Ligature of the femoral artery at the apex of the 

 femoral trigone is carried out by means of an incision along 

 the line of the vessel. The sartorius is identified and retracted 

 to the lateral side, exposing the artery just before it enters the 

 adductor canal (of Hunter). In this situation the vessel is 

 crossed by the medial cutaneous nerve, and the saphenous nerve 

 may be either an anterior or. a lateral relation. Although lying 

 to the medial side of the artery in the proximal part of the 

 thigh, the femoral vein occupies a posterior position at the apex 

 of the trigone, and care must be taken not to injure it when pass- 

 ing the ligature. On this account the fibrous sheath of the 

 artery is opened on its antero-lateral aspect. 



After ligature of the artery at this site, the circulation is re- 

 established by means of the anastomosis round th'e knee-joint 

 (p. 445), where branches which arise from the femoral on the 

 proximal side of the ligature communicate with others which 

 arise on the distal side. 



