THE SPINAL NERVES. 



135 



FIG. 63. 



Describe the Lumbar Plexus. It is formed by communicating loops from 

 the anterior branches of the first 4 lumbar nerves, in the following manner. 

 From the FIRST lumbar nerve are given off the 

 Ilio-hypogastric, to the abdominal and gluteal regions. 

 Ilio-inguinal, to the inguinal region and the scrotum. 

 Communicating Loop, to the second lumbar nerve. 

 From the SECOND lumbar nerve are given off the 

 External Cutaneous, to the integument of the outside 



of the thigh. 

 Genito-crural, to the spermatic cord and front of the 



thigh. 



Communicating Branch, to the third lumbar nerve. 

 From the THIRD and FOURTH lumbar nerves are given 

 off the following by a branch of origin from each, 

 viz. 



Obturator, through the obturator foramen to the ex- 

 ternal obturator and adductor muscles and the hip- 

 and knee-joints. 

 Accessory Obturator (often absent), to the pectineus 



and hip-joint. 



Communicating, from the 3d lumbar to the 4th. 

 Communicating, from the 4th lumbar to the 5th. 

 Anterior Crural, which descends through the psoas 

 muscle, and beneath Poupart's ligament to the 

 thigh, where it divides into an anterior and pos- 

 terior division. Its branches are, 



To the Iliacus muscle. Long Saphenous. 



To the Femoral artery. Muscular. 



Middle and Internal Cutaneous. Articular. 



Describe the Sacral Plexus .d It is formed by the 

 anion of the upper 4 sacral nerves^ with the 5th lum- 

 bar and a loop from the 4th, the two latter forming the 

 Lumbo-sacral Cord.* It lies upon the pyriformis muscle 

 and gives off the following 5 branches, viz. 



Superior Gluteal^ from the lumbo-sacral cord, sup- 

 plies the glutei and tensor vaginae femoris. 



Muscular Branches, to the pyriformis, obturator internus, gemelli, and quad- 

 ratus femoris muscles. 



Pudicf escapes by the great sacro-sciatic foramen, crosses the ischiatifl 



