BRANCHES OF THE SACRAL PLEXUS 



811 



6. Till' small sciatic nerve springs from the posterior aspect of the second and 

 third saenil nerves, and, passing downwards, escapes through the great sacro-sciatic 

 foramen by passing below the pyriformis. It then rims downwards on the posterior 

 surface of the great sciatic nerve, under cover of the gluteus maximus muscle, to 

 wdiich it furnishes a branch. This branch is i)rol)ably a portion of the inferior 

 gluteal nerve, which has adhered in a i»art of its course to the small sciatic. 

 p]merging from beneath the gluteus maximus it crosses the biceps, accomi>anicd l)y 

 a branch of the sciatic artery, and passing down, beneath the deep fascia it enters 



Fig. 4G5. — Diagram of the Lumbar and Sacral Plexuses. (Modified from Paterson.) 



FROM LAST THORACIC 



FIRfiT LUMBAR 



SECOND L UMBA R 



GEyiTO-CRVRAL 



ILIO-H YPO GA STRI C 



ILIO-IXGIINAL 



EXTERXA L 

 CVTAXEOIS 



OBTURATOR 



A CCESSOR Y 

 OBTURATOR 



BRANCH TO ILIACUS 

 ANTERIOR CRURAL 



S UPERIOR G L UTEA L 

 INFERIOR GLUTEAL 



GREA T SCIA TIC 



NERVE TO 

 QUADRATIC 



FEMORIS 



EXTERNA L 



POPLITEA L 



SECTION 



IXTERXA L 



POPLITEAL 



SECTION 



THIRD LUMBAR 



FO UR TH L UMBA R 



FIFTH LUMBAR 



FIRST SACRAL 



SECOND SACRAL 



THIRD SACRAL 



VISCERAL 

 FOURTH SACRAL 



PERFORA TING 



CUTANEOUS 

 PERIXEAL 

 FIFTH SACRAL 

 KEKVE TO roCCYGEVS 

 NER VE TO LE VA TOR 

 ANI 



FIRST COCCYGEAL 



VISCERAL 



TO HAMSTRINGS /' SMALL SCIATIC 

 NERVE TO OBTURATOR INTERNES 



PUDIC 



the popliteal space and pierces the deep fascia of the leg a little below the knee, 

 ending in the integument of the upper part of the calf, where it may connnunicate 

 with the external saphenous nerve. In its course down the thigh it gives off 

 numerous branches, which pierce the fascia lata to supply the skin covering the 

 back of the thigh and the popliteal space. At the lower border of the gluteus 

 maximus it gives off (a) reflected Immches, and (6) a large branch termed the 

 long pudendal nerve. 



\a) The reflected branches, three or four in number, wind round the lower 



