1 82 INFERIOR EXTREMITY 



looks distally and laterally, whilst its abdominal surface 

 is directed upwards and medially. 



Dissection. The exposure of the femoral sheath is the next step in the 

 dissection of the thigh. To attain this object the iliac portion of the fascia 

 lata must be partially reflected. Divide the superior horn of the lateral 

 crescentic margin of the fossa ovalis, and then carry the knife laterally 

 along the lower border of the inguinal ligament, so as to sever the 

 attachment of the fascia lata to this thickened band. This incision should 

 extend to within an inch of the anterior superior spine of the ilium. The 

 piece of fascia marked out by the incision above, and by the lateral free 

 margin of the fossa ovalis medially, must be carefully raised from the 

 subjacent femoral sheath and thrown distally and laterally. On the 

 removal of a little loose fat, the femora! sheath will be brought into view as 

 it enters the thigh under the inguinal ligament. Isolate it carefully from 

 adjacent and surrounding parts, by carrying the handle of the knife gently 

 round it insinuating it first between the sheath and the inguinal ligament, 

 then between the sheath and the lacunar ligament, which lies medial to it. 



Femoral Sheath. The funnel-shaped appearance of the 

 femoral sheath will now be apparent the wide mouth of 

 the membranous tube being directed upwards into the 

 abdomen, and the narrow inferior part gradually closing 

 upon the vessels, and fusing with their coats about the level 

 of the distal limit of the fossa ovalis. Whilst it presents this 

 appearance, however, it should be noticed that its sides 

 do not slope equally towards each other. The lateral border 

 of the sheath is nearly vertical in its direction, whilst the 

 medial wall proceeds very obliquely distally and laterally. 

 If the dissection has been successfully performed, the 

 lumbo-inguinal nerve should be seen piercing the lateral 

 wall of the sheath, whilst the great saphenous vein, and 

 some lymph vessels, perforate its anterior and medial walls. 

 Further, if the subject be spare and the fasciae well marked, 

 the dissector will in all probability notice that the anterior 

 wall of the sheath, in its proximal part, is strengthened by 

 some transverse fibres which pursue an arched course across 

 it. To these fibres the name of deep femoral arch is given, in 

 contradistinction to the term superficial femoral arch, which is 

 sometimes applied to the inguinal ligament. In favourable 

 circumstances the deep femoral arch may be observed to 

 spring from the deep surface of the inguinal ligament about 

 its middle. After traversing the front of the sheath the 

 band expands somewhat, and is attached by its medial 

 extremity to the ilio-pectineal line or pecten of the pubic bone 

 behind the lacunar ligament. 



Constitution of the Femoral Sheath. The source from 



