THE LOWER LIMB 597 



parts of the opening displayed. Before disturbing the opening, the dis- 

 sector should note that a part of the anterior waU of the femoral sheath is 

 seen lying within it. Having studied the saphenous opening, the dissector 

 should now separate the outer border of the opening from the anterior wall 

 of the femoral sheath by dividing the fibrous processes which connect them. 

 The superior comu is next to be detached from Poupart's Hgament, and 

 turned downwards and outwards along with the outer border of the opening. 

 This will bring fully into view the anterior wall of the femoral sheath. The 

 deep femoral arch should be shown at this stage as a bundle of fibres extending 

 from the centre of Poupart's hgament on its deep aspect inwards over the 

 anterior wall of the femoral sheath to the pectineal portion of the iUo-pectineal 

 hne, where it is attached behind Gimbemat's hgament. 



Having studied the sheath as it now appears, and having observed that the 

 femoral branch of the genito-femoral nerve pierces the outer part of the sheath 

 just below Poupart's ligament, three vertical incisions are to be made in its 

 anterior wall — one over the femoral artery, another over the femoral vein, and 

 a third a Une or two internal to the vein. The interior of the sheath should 

 then be shown to be divided into three compartments by means of two septa, 

 which pass backwards on either side of the femoral vein. The femoral artery 

 and, for a very Umited distance, the femoral branch of the genito-femoral nerve 

 should be shown in the outer compartment, whilst the femoral vein, having 

 on its inner side two or three of the deep femoral (deep inguinal) glands will 

 be found in the middle compartment. The inner compartment is called the 

 femoral canal. It is of considerable surgical importance, and should be studied 

 with the closest attention. It will be seen to contain a little fat, and at its 

 upper end one of the deep femoral glands will be found. The dissectors of 

 the thigh and abdomen, who should be working in concert at this stage, should 

 now thoroughly explore the canal. The httle finger should be inserted into 

 it, and carried upwards to a point beneath Poupart's hgament. At the upper 

 end of the caUcJ the finger will detect the septum femorale, which shuts off the 

 canal from the abdominal cavity. By breaking down this septum, the point 

 of the finger will lie in the femoral ring, and the sharp wiry base of Gimbernat's 

 hgament will readily be felt on the inner side of the ring, this being the usu£d 

 cause of stricture in femoral hernia. Behind the finger as it Ues in the femoral 

 ring is Cooper's ligament. This structure, however, can only be shown by 

 making a deep dissection of the parts beneath Poupart's hgament, in con- 

 junction with the dissector of the abdomen. The parts around the femoral 

 ring should be studied with the greatest care, as it is through this ring and the 

 femoral canal that femoral hernia may occur. 



The remainder of the skin of the thigh is now to be removed by making a 

 vertical incision down the inner side of the thigh to a point just below the 

 level of the patella, and carrying this incision transversely across the front 

 of the leg immediately below the patella on to the outer aspect of the hmb. 

 This will enable the dissector to reflect the skin from the patella as well as 

 from the front of the thigh. The prepatellar bursa will be found lying in 

 front of the bone, where it is confined by an expansion which the fascia 

 lata sends over the bone from its lateral borders. 



A complete dissection of the cutaneous nerves and the femoral part of the 

 long saphenous vein is now to be made. The external cutaneous nerve, 

 which has been already caught, should now be followed out. Its small 

 posterior division and large anterior di\'ision should be shown, and it should 

 be noted that the latter is contained in a tube of fascia lata for about 4 inches 

 before it enters the integument. The middle cutaneous nerve will be found 

 piercing the fascia lata (usually in two divisions) about 4 inches below Poupart's 

 hgament, and both should be followed down to the patellar plexus. It has 

 been seen that the inguinal nerve is distributed to the integument of the 

 inner aspect of the thigh in its upper third. In dissecting the long saphenous 

 vein in the middle third of the thigh, twigs of the internal cutaneous nerve 

 will be met with along the course of that vein. There may also be found 

 branches of the subsartorial plexus ramifying in this region (middle third). 

 Another nerve which should be looked for at this level is the cutaneous 



