804 



THE NERVOUS SYSTEM 



nerve in a plexiform manner. It pierces the internal oblique a little in front of the 

 anterior superit)r spine of the ilium, and runs forwards under cover of the aponeu- 

 rosis of the external oblique innnediately above Poui)art's ligament, enters the 

 lower part of the inguinal canal and reaches the external abdominal ring. It then 

 traverses the ring and divides into its terminal brandies, whicli are distributed to 

 the skin covering the upper part of the adductor longus. the integuments of the 

 scrotum in the male, and of the labium majus in the female. 



(3) The genito-crural nerve arises from the first and second lumbar nerve by 

 two roots which pass forwards and downwards through the fibres of the psoas, and 

 unite to form a single trunk. The nerve then appears on the surface of the psoas 



Fig. 462. — Branches of the Lumbar and Sacral Plexus viewed from before. 

 (After Hirschfeld and Leveille. ) 

 GAXGLIATED CORD OF SYMPATHETIC AORTIC PLEXUS 



LAST THORACIC NERVE JfT^^TV / , LAST THORACIC NERVE 



FIRST L 



ILIO- 

 HYPOGASTRIC 

 TLIO-INGUIXAL 



SECOND 

 LUMBAR 



FOURTH 



LUMBAR 



ILIO-INGUINAL 



EXTERNAL 



CUTANEOUS 



GEXITO-CRVRAL 



LCMBO- SACRAL 



CORD 



ANTERIOR CRURAL 



OBTURATOR 



ILIO-INGUINAL 



DISTRIBU- I 



TION OF 

 EXTERNAL \ 

 CUTANEOUS 



CRURAL 

 BRANCH 

 OF GENITO- 

 CRURAL 



ILIO-HYPO. 

 GASTRIC 



ILIO- 

 INGUINAL 



THIRD 

 LUMBAR 

 NERVE 



GENITO- 

 CRURAL 



EXTERNA L 

 CUTANEOUS 



GENITAL 

 BRANCH 

 OF 

 GENITO- 



CRURAL 



CRURAL 

 BRANCH OF 

 GENITO- 

 CRURAL 



OBTU- 

 RATOR 



SACRAL 

 PLEXUS 



close to the vertebral column, at the level of the third lumbar vertebra and runs 

 downwards under cover of the peritoneum. After lieing crossed by the ureter it 

 readies the outer side of the external iliac artery, where it divides into a genital 

 and a crural branch. 



(a) The genital branch accompanies the s]->ermatic vessels through the inguinal 

 canal, and, emerging from the external al)dominal ring, pierces the internal sper- 

 matic fascia, and is distributed to the cremaster muscle. In the female this branch 

 is rudimentary and accompanies the round ligament. 



(6) The crural branch is carried downwards in front of the external iliac and 

 femoral artery into tlie external compartment of the femoral sheath. It pierces the 

 femoral sheath and becomes subcutaneous about two inches below Poupart's liga- 



