THE THIGH 245 



seeing that it is the base of the lacunar ligament against which the surgeon's 

 knife is generally directed for the relief of strictured femoral hernia. 



Dissection. The boundaries and contents of the femoral 

 triangle, which occupies the proximal third of the anterior part 

 of the thigh, must now be dissected. Commence by cleaning 

 the medial and lateral boundaries. The lateral boundary is 

 formed by the proximal third of the sartorius muscle, and the 

 medial boundary by the medial border of the adductor longus 

 muscle. To clean a muscle properly the following rules must 

 be observed : (i) Keep the muscle tense by bending or straighten- 

 ing the limb or by rotating it. (2) Make all cuts with the scalpel 

 parallel with muscle fibres. (3) Remove the fascia in one con- 

 tinuous layer from one border of the muscle to another. (4) 

 Define very carefully the borders of the muscle. 



As the deep fascia is removed the scalpel must cut not only 

 parallel with the muscle fibres but also against them, in order 

 that none of the deep fascia may be left on the muscle. 



Clean the sartorius first from its origin on the anterior border 

 of the ilium, below the anterior superior spine, to the point where 

 it crosses the adductor longus at the junction of the proximal 

 and middle thirds of the thigh. Begin at its medial or its 

 lateral border, whichever is more convenient, and take care not 

 to injure the lateral cutaneous nerve of the thigh, which crosses 

 superficial to the muscle near its origin, and the intermediate 

 cutaneous nerve, which either pierces or crosses the muscle near 

 the middle line of the thigh. 



Next clean the pectineal fascia from the anterior surface of 

 the adductor longus from the point where the muscle arises 

 from the front of the pubis to the point where it disappears 

 behind the sartorius at the apex of the femoral trigone. 



When the medial and lateral boundaries of the trigone have 

 been displayed proceed to the dissection of the femoral nerve 

 and its branches. Place a block under the knee in order to 

 flex the hip- joint and relax the boundaries and contents of the 

 triangle, then follow the intermediate cutaneous nerve upwards 

 to the point where it springs from the front of the trunk of the 

 femoral nerve, next clean the lateral border of the trunk, and 

 inserting the handle of a spare scalpel behind the nerve raise it 

 from the groove between the iliacus and psoas in which it lies. 

 Leave the spare scalpel behind the nerve trunk and clean its 

 various branches so far as t they lie in the femoral trigone. 

 Medial to the intermediate cutaneous nerve lies the medial 

 cutaneous nerve of the thigh. It springs from the front of the 

 trunk of the femoral nerve, runs along the lateral border of 

 the femoral sheath and crosses the front of the femoral artery 

 at the apex of the trigone. On a plane posterior to the inter- 

 mediate and medial cutaneous nerves lie the deeper branches of 

 the femoral nerve. They radiate from the extremity of the 

 trunk of the nerve and are arranged in the following order from 

 above and laterally downwards and medially : the nerve to 

 the rectus femoris, the nerve to the vastus latralis, the nerve 

 to the vastus intermedius, the nerve to the vastus medialis, and 

 the saphenous nerve. The nerve to the sartorius is usually a 

 branch of the intermediate cutaneous nerve. As the muscular 

 branches are being cleaned take care to avoid injury to the 



