THE SACRAL PLEXUS. 



669 



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 of 



Fig. 441. 



Fig. 441. DIAGRAMMATIC 

 OUTLINE OP THE LUMBAR 

 AND SACRAL PLEXUSES WITH 

 THE PRINCIPAL NERYKS 



ARISING FROM THEM. ^ 



The references to the nerves 

 of the lumbar plexus will be 

 found at p. 659. DXII, 

 roots of the last dorsal nerve ; 

 LI to V, roots of the five 

 lumbar nerves ; SI to V, and 

 CI, roots of the five sacral 

 and the coccygeal nerves ; 

 IV, V, loop from the an- 

 terior primary branches of 

 the fourth and fifth lumbar 

 nerves, forming the lumbo- 

 sacral cord ; 3, superior glu- 

 teal nerve ; SO, sacral plexus 

 ending in the great sciatic 

 nerve ; 4, lesser sciatic nerve, 

 rising from the plexus pos- 

 teriorly ; 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- 

 inellus inferior, quadratus and 

 hip-joint ; 7, twigs to the 

 pyriformis ; 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, which passes 

 round the lower border of the 

 gluteus maximus; 11, coccy- 

 geal branches. 



the fifth and part of the 

 fourth lumbar nerves), 

 the anterior divisions 

 of the first three sacral 

 nerves, and part of the 

 fourth, unite to form 

 this plexus. Its con- 

 struction differs from 

 that of the other spi- 

 nal nervous plexuses 

 in this respest, that the several constituent nerves entering into it 



ci 



