THE LUMBAR PLEXUS. 



599 



two branches proceed ; one of these, the larger, forms part of the 

 anterior crural nerve ; the other, a part of the obturator nerve. The 

 fourth nerve gives two branches, which serve to complete the obturator 



Dxn 



Fig. 366. — DiAGRAMilATIC 



Outline of the Lumbar 

 AND Sacral Plexuses with 



THE PRINCIPAL NeRVES 

 ARISING FROM THEM. ^ 



D,XII, placed opposite the 

 divided roots of the last dorsal 

 nerve ; L,I 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 ; S,I to V, and C,I, 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 ; oh, 

 obturator nerve from the se- 

 cond, third, and fourth lumbar 

 nerves ; oh, accessory obtura- 

 tor ; IV', y, 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 fii'st, second, third, and 

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

 fourth, which passes round the lowe; border of the gluteus ma.ximus ; 11, coccygeal 

 branches. 



