402 THE INFERIOR EXTREMITY 



(Key's ligament} arches proximally and medially to reach the 

 pubic tubercle, where it blends with the lacunar ligament (of 

 Gimbernat). The inferior cornu (Burns' ligament) is also well 

 marked, and lies just distal to the point of union of the great 

 saphenous and femoral veins (Fig. 119). The medial border of 

 the fossa is poorly denned. It is formed by the fascia over the 

 pectineus, and, when traced laterally, it disappears behind the 

 femoral sheath and blends with its posterior wall. 



The fossa ovalis is i| inches long by half an inch wide, and 

 is of particular importance because it represents the distal 

 opening of the track taken by a femoral hernia after it has 

 passed through the femoral (crural) ring (p. 403). 



The lateral intermuscular septum is a strong partition which 

 connects the deep fascia to the lateral lip of the linea aspera 

 of the femur. It separates the vastus lateralis from the femoral 

 head of the biceps, and thus forms a partition between the 

 extensor and flexor compartments of the thigh. Incisions to 

 expose the diaphysis of the femur are made in front of the line 

 of the lateral intermuscular septum (p. 437). 



The medial intermuscular septum separates the adductor 

 from the extensor compartment of the thigh. As it covers the 

 anterior surfaces of the adductor longus and magnus, it forms 

 the fascial floor of the adductor canal (of Hunter). 



The Femoral Sheath is a sleeve-like prolongation of the 

 fascial envelope of the abdomen (p. 271) which passes down into 

 the thigh behind the inguinal ligament. Lateral to the femoral 

 vessels, both the fascia transversalis and the fascia iliaca are 

 attached to the inguinal ligament; but opposite the vessels, 

 which intervene between the two layers, they are carried into 

 the thigh to form the femoral sheath (Fig. 120). 



Two fascial septa divide the sheath into three compartments ; 

 the lateral compartment contains the femoral artery and the 

 lumbo-inguinal nerve and is the longest of the three (Fig. 121). 

 The middle compartment contains the femoral vein. The 

 medial compartment, which is the shortest of the three, only 

 contains some extra-peritoneal fat and one of the deep sub- 

 inguinal lymph glands, which together constitute the septum 

 femorale (crurale) ; it is known as the femoral (crural) canal, and 

 is of great importance because it constitutes the passage through 

 which a femoral hernia enters the thigh. 



The femoral sheath is related anteriorly to the fascia lata 

 and the fossa ovalis ; posteriorly, it rests on the pectineus, 



