242 THE INFERIOR EXTREMITY 



lateral to the femoral sheath, it is prolonged over the ilio- 

 psoas muscle ; whilst from its posterior aspect a lamina is 

 given off which passes posterior to that muscle and joins the 

 capsule of the hip joint (Fig. 113). 



Dissection. The femoral sheath must be opened, in order 

 that the arrangement of parts inside may be displayed. Make 

 three vertical and parallel incisions through the anterior wall 

 one over the femoral artery, which occupies the lateral part of 

 the sheath, another over the femoral vein in the line of the 

 great saphenous vein, and the third about half an inch medial 

 to the second. The first two should begin at the level of the 

 inguinal ligament, and should extend distally for an inch and a 

 half. The most medial of the three incisions should commence 

 at the same level, but should be carried distally only for half an 

 inch or less. 



Interior of the Femoral Sheath. A little dissection will 

 show that the sheath is subdivided, by two antero-posterior 

 partitions, into three compartments. The femoral artery and 

 lumbo-inguinal nerve occupy the most lateral compartment ; the 

 femoral vein fills up the intermediate compartment ; whilst in 

 the most medial compartment are lodged a little loose areolar 

 tissue, a small lymph gland, and some lymph vessels. This 

 last compartment, from its relation to femoral hernia, has the 

 special name of femoral canal applied to it. 



Canalis Femoralis. The boundaries and extent of the 

 femoral canal must be very thoroughly studied. The best 

 way to commence the study is to introduce the little finger 

 into the canal and push it gently upwards. The length of 

 the canal is not nearly so great as that of the other two 

 compartments. Indeed, it is not more than half an inch 

 long. Distally it is closed, and it rapidly diminishes in 

 width proximo -distally. Its proximal aperture lies on the 

 lateral side of the base of the lacunar ligament, and is called 

 the femoral ring. It is closed by the closely applied extra- 

 peritoneal fatty tissue of the abdominal wall. The parts 

 which immediately surround the opening can be readily 

 detected with the finger : laterally the femoral vein, medially 

 the sharp crescentic base of the lacunar ligament, anteriorly 

 the inguinal ligament, and posteriorly the pubic bone covered 

 by the pectineus muscle. The portion of the extra-peritoneal 

 fatty tissue which closes the ring is called the septum 

 femorale. On the abdominal surface of the septum femorale 

 is the peritoneal lining of the abdominal cavity, and when 

 examined from above both are seen to be slightly depressed 



