THE SACRAL PLEXUS. 



609 



spinal canal by the terminal opening, pierces the sacro-sciatic ligament 

 and the coccygeus muscle, and, being joined upon the side of the coccyx 

 with the fifth sacral nerve, partakes in the distribution of that nerve. 



THE SACRAL PLEXUS. 



The lumbo-sacral cord (resulting as before described from the junction 



Fig. 371. DlAQRAMJIATIO 



OUTLIKE OF THE LuJIBAR 



AND Sacral Plexuses with 



THE PRINCIPAL NeRTES 

 ARISING FROM THEJI. (A.T.) 



Tlie references to the nerves 

 of the lumbar plexus will be 

 found at p. 599. IV', V, 

 loop from the anterior primary 

 branches of the fourth and fifth 

 lumbar nerves, forming 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 ge- 

 mellus inferior, quadratiis and 

 hip-joint ; 7, twigs to the 

 pyi-iformis ; 8, 8, pudic from 

 the first, second, third, and 

 fourth sacral ; 9, visceral 

 branches ; 9', twig to the 

 levator ani ; 10, cutaneous 

 from the fourth, whicb passes 

 ro\ind the lower border of the 

 gluteus maximus ; 11, coccy- 

 geal branches. 



of the fifth and part of the 

 fourthlumbar nerves), the 

 anterior divisions of the 

 first three sacral nerves, 

 and part of the fourth, 

 unite to form this plexus. 

 Its construction differs 

 from that of the other 

 spinal nervous plexuses in 

 this respect, that the 

 several constituent nerves 

 entering into it unite into 

 one broad flat cord. To 

 the place of union the 

 nerves proceed indifferent 

 directions, that of the upper 



VOL. 1. 



Fig. 371. 



ones being obliquely downwards, while 



