LUMBAR PLEXUSES 



803 



an hypoirastric branch, (a) The iliac branch j^icrees the internal and external 

 obli(|Ue muscles and crosses the crest of the ilium, lying close to the bone. It is 

 directed downwards towards the great tnjchanter of the fenmr; some of its twigs reach 

 as far as that prominence, and su})ply the integuments covering the fore part of the 

 gluteal region, (b) The hypogastric branch continues the direction of the main 

 trunk, and perforates the internal ol)lique near the anterior superior spine of the 

 iHum. In this part of its course it communicates in a plexiform manner with the 

 ilio-inguinal nerve. It is then directed forwards and inwards under cover of the 



Fig. 461. — Diagram of the Lumbar axd Sacral Plexuses. (Modified from Pate rson.) 



FHOM LAST THORACIC 



FIRST LUMBAR 



SECOSD LUMBAR 



OEXITO-CRURAL 



ILIO-HYPOGASTRIC 



ILIO-IXGUIXAL 



EXTERXAL 

 CUTAXEOUS 



OBTURA TOR 



A CCESSOR r 

 OBTURATOR 



BRAXCII TO ILIACUS 

 AXTERIOR CRURAL 



SUPERIOR GLUTEAL 

 IXFERIOR GLUTEAL 



GREA T SCIA TIC 



XERVE TO 



QUADRATUS 



FEMORLS 



EXTERXAL 



POPLITEAL 



SECTIOX 



IXTERXA L 



POPLITEAL 



SECTIOX 



TO HAMSTRIXGS 



THIRD LUMBAR 



FOURTH L UMBAR 



FIFTH LUMBAR 



FIRST SACRAL 



SECOXD SACRAL 



THIRD SACRAL 



VISCERAL 

 FOURTH SACRAL 



PERFORA TIXG 



CUTAXEOUS 

 PERIX^EAL 

 FIFTH SACRAL 



KERVE TO COffYGErs 



XER VE TO LEVA TOR 

 A XI 



FIRST COCCYGEAL 



VISCERAL 



SMALL SCIATIC 

 XERVE TO OBTURATOR IXTERXUS 



PUDIC 



aponeur()sis of the external ol)li(jue. Finally it pierces the aponeurosis outside the 

 sheatJi of the rectus at a point a1)out an inch above the external abdominal ring, 

 and .supi)lies the skin in that situation, forming a continuation of the series of 

 anterior cutaneous nerves of tlie abdomen. 



(2) The ilio-inguinal nerve arises from the first luml)ar nerve in common 

 Avith the ilio-hypogastric. and acc(jmpanies the last-named nerve acro.ss the quad- 

 ratus lumborum, but at a Liwer level. It then passes ol)liriuolv across the upj.er 

 part cf the ihacus and pierces the transversalis muscle. It f<.ll..ws the curve of the 

 crest of the ilium in company with the ilio-hypoga.stric. connnunicatin- witli tliat 



