THE THIGH 225 



and leave them. The proximal group lies parallel with the 

 inguinal ligament, the distal group lies along the sides of the 

 proximal part of the great saphenous vein. (4) Six nerves 

 the ilio-inguinal, the lumbo-inguinal, the lateral cutaneous 

 nerve of the thigh, the intermediate cutaneous nerve of the 

 thigh, the medial cutaneous nerve of the thigh, the saphenous 

 nerve. The first three nerves mentioned are derived directly 

 from a plexus of nerves inside the abdomen called the lumbar 

 plexus and the last three are branches of the femoral nerve, 

 which is itself a branch of the lumbar plexus. (5) The fossa 

 ovalis. (6) The patellar bursa, and (7) the deep fascia of the 

 thigh. 



Commence by cleaning the great saphenous vein. It is 

 easily found about the mid-length of the thigh, near the medial 

 border. Cut down upon it there and then, with the point 

 and handle of the scalpel, clean away the fascia from its walls, 

 but do not injure its tributaries. Follow the vein, distally, to 

 the posterior border of the medial side of the knee and, proximally, 

 towards a point situated about 4 cm. below and lateral to the 

 pubic tubercle. 



As the proximal end of the vein is approached lift it from 

 the bed of superficial fascia in which it lies ; insert the handle 

 of the scalpel behind the vein and push it upwards, until it 

 slips through an opening in the fascia lata through which 

 the vein passes on its way to join to the femoral vein. The 

 opening in the fascia lata is the fossa ovalis. The layer 

 of the deep fascia which covers the fossa ovalis is called 

 the cribriform fascia. The centre of the opening is situated 

 about 35-40 mm. distal and lateral to the pubic tubercle, 

 and its distal margin is always easily demonstrated in the way 

 already indicated. Do not attempt at present to display its 

 other boundaries ; they will be dissected later. When the 

 proximal part of the vein is being cleaned a number of the more 

 distal subinguinal lymph glands will be seen, some lying lateral 

 and some medial to the vein. They are rounded or ovoid bodies 

 of greyish or yellowish-pink colour, and they vary greatly in 

 size, some being as small as a pin-head, others as large as a 

 large bean. Connected with them the dissector will find a 

 large number of fine white strands which are the lymph vessels 

 passing to and from the glands. Clean the glands and some of 

 the lymph vessels, but do not disturb them from their positions 

 at present. Then proceed to clean the other superficial blood- 

 vessels. They are the superficial external pudendal, the super- 

 ficial epigastric, and the superficial circumflex iliac veins and 

 arteries. Begin with the veins which terminate in the great 

 saphenous vein before it passes through the fossa ovalis. Follow 

 them from their terminations towards their commencements, 

 and at the same time clean the accompanying arteries, which 

 are branches of the femoral artery, but avoid injury to the 

 superficial lymph glands which will be met with as the dissection 

 proceeds. Two of the arteries, the superficial external pudendal 

 and the superficial epigastric, emerge through the fossa ovalis : 

 the superficial circumflex iliac artery will be found, as a rule, 

 piercing the deep fascia lateral to the fossa. The lymph glands 

 will be recognised by their firm consistence and their greyish or 

 yellowish-pink colour. 



VOL. I 15 



