32 



proximal portion of the muscle taking care not to cut the small nerve 

 branches it receives from the N. saphenus internus (PI. V, 47, 48) (a branch 

 of the N. femoralis) which lies immediately beneath the proximal half of 

 the sartorius; also do not disturb the deep inguinal lymph gland which 

 lies in the interstice between the sartorius and the pectineus (PI. V, 63). 

 As the N. femoralis crosses the tendon of the psoas magnus it gives off the 

 large branch just mentioned, N. saphenus internus, which runs beneath 

 the sartorius for about one-half the length of the muscle, supplies small 

 branches to it, as just stated. It then emerges with the A. and V. saphena 

 interna, from between the adjacent borders of the sartorius and gracilis, 

 near the middle of the thigh, where it breaks up into several large sub- 

 cutaneous branches which are distributed to the inner and anterior faces 

 of the thigh and leg. The longest of these branches accompanies the 

 A. and V. saphena interna to the flexor side of the tarsus. Frequently the 

 N. saphenus internus is divided into two parallel branches. After giving 

 off the N. saphenus internus the main trunk of the N. femoralis, together 

 with a large artery and vein, passes between the rectus femoris and the 

 vastus internus into the quadriceps femoris group of muscles. Dissect 

 between the vastus internus and the rectus femoris; transect the rectus 

 femoris 10 to 15 cm. from its attachment to the patella and reflect the 

 ends. The vastus internus also may be partially transected, if desired. 

 Now trace the N. femoralis to its termination in the rectus femoris, vastus 

 internus, vastus externus, and vastus intermedius. The small M. capsu- 

 laris is not supplied by this nerve but by one of the gluteal nerves as 

 mentioned later. 



Exposure of the A. iliaca interna, the A. sacralis lateralis and the sacral 

 nerves (PI. V, 34, 35, 52, 54, 55, 56, 57, 60). 



Turn the rectum and other pelvic organs ventrally and find the small 

 nerves (PI. V, 58) 2 to 4 in number, which lie between the peritoneum and 

 the sacro-sciatic ligament and extend from the 2d, 3d, and 4th or from the 

 3d and 4th only, sacral nerves towards the lateral side of the pelvic organs 

 where, in connection with branches of the sympathetic nerve, they form 

 an intricate network of nerves known as the hypogastric or pelvic plexus 

 (PL V, 51). (If put on the stretch these two or more small nerves will 

 stand out as more or less tense bands.) Great care must be exercised in 

 exposing the A. (and V.) sacralis lateralis and the sacral nerves, because 

 of their intimate relation to each other and to the sacro-sciatic ligament. 

 Cut the ligament along the ventral mid surface of the V. sacralis lateralis 

 and careftdly turn it from the vein. It will now be seen that the largest 

 of the sacral nerves, N. ischiadicus, 5 to 8 cm. in width (PL V, 54), originates 

 from the 5th and 6th lumbar and the ist and 2d sacral nerves. This large 



