THE LUMBAR PLEXUS AND NEKVES. 



659 



The branches of this plexus form two sets, which are distributed, one to 

 the lower part of the wall of the abdomen, the other to the fore part and 

 inner side of the lower liinb. In the former set are the ilio-hypogastric and 



Fig. 436. DIAGRAMMATIC 

 OUTLINE OF THE LUMBAR 

 AND SACRAL PLEXUSES WITH 

 THE PRINCIPAL NERVES 



ARISING FROM THEM. 4 



Fig. 436. 



DXIT 



DXII, placed opposite the 

 divided roots of the last dorsal 

 nerve ; LI to V, opposite the 

 roots of the five lumbar nerves : 

 the loops uniting the anterior 

 primary divisions of these 

 nerves together, and the first 

 with the twelfth dorsal are 

 shown; SI to V, and CI, the 

 same in the sacral and coccy- 

 geal nerves ; p, placed on some 

 of the nerves marks the pos- 

 terior primary divisions cut 

 short ; p' p, the plexus formed 

 by the union of the posterior 

 branches of the third, fourth, 

 and fifth sacral and the coccy- 

 geal nerves ; d, the abdominal 

 continuation of the last dorsal 

 nerve, from which d' the iliac 

 cutaneous branch arises; 1, 1', 

 the ilio-hypogastric and ilio- 

 inguinal branches of the first 

 lumbar nerve ; 2, the genito- 

 crural rising by a loop from 

 the first and second lumbar; 

 2', external cutaneous of the 

 thigh rising by a loop from the 

 second and third ; ps, branches 

 to the psoas muscle along the 

 lumbar plexus ; cr, anterior 

 crural nerve from the second, 

 third, and fourth lumbar; il, 

 branches to the iliacus ; ob, 

 obturator nerve from the se- 

 cond, third and fourth lumbar 

 nerves ; ob', accessory obtura- 

 tor; IV, V, loop from the 

 fourth and fifth lumbar, form- 

 ing the lumbo- sacral cord ; 3, 

 superior gluteal nerve ; sc, 

 sacral plexus ending in the great 

 sciatic nerve ; 4, lesser sciatic 

 nerve rising from the plexus 

 posteriorly; 4', inferior gluteal 

 branches ; 5, inferior puden- 

 dal ; 5', posterior cutaneous 

 of the thigh and leg ; 6, 6, 

 branches to the obturator in- 



ternus and gemellus superior ; 6', 6', branches to the gemellus inferior, quadratus and 

 hip-joint ; 7, twigs to the pyriformis ; 8, 8, pudic nerve from the first, second, third, and 

 fourth sacral ; 9, visceral branches ; 9', twig to the levator ani ; 10, cutaneous from the 

 fourth, which passes round the lower border of the gluteus maximus ; 11, coccygeal 

 branches. 



IV 



V 



CI 



