ABDOMINAL SPINAL NERVES. 635 



ing to Bichat, of the superior, middle, and inferior musculo- 

 cutaneous. 



The superior musculo-cutaneous (called also external ilio- 

 inguinal, ilio-liypogastric, ilio-scrotal) conies from the supe- 

 rior part of the plexus, passes outwardly through the psoas 

 inagnus to the quadratus lumborum, and thence to the 

 back part of the crest of the ilium, here it divides into an 

 external and internal branch. The former supplies the ab- 

 dominal muscles and integuments. The internal can be 

 traced forward to the anterior superior spinous process of 

 the ilium, and thence across parallel with Poupart's liga- 

 ment to near the rectus, where it perforates the external 

 oblique, and becomes cutaneous upon the pubic and ingui- 

 nal regions. 



The middle musculo-cutaneous , or inguino-cutaneous , has 

 nearly a similar origin and distribution with the last. 



The inferior musculo-cutaneous, or external cutaneous , 

 comes from the first or second lumbar, passes along the 

 iliacus muscle, and between the anterior superior and an- 

 terior inferior spinous processes, divides into an anterior and 

 posterior branch. The former perforating the fascia lata 

 about three or four inches below Poupart's ligament, be- 

 comes cutaneous, distributing filaments as low as the knee. 

 The posterior is spent on the outer and back part of the 

 thigh, either passing through or behind the tensor vaginse 

 femoris. 



The genito crural comes from the second or third lumbar 

 nerve. The genital or spermatic branch joins the cord at the 

 internal ring, supplies the cremaster, and terminates upon 

 the integuments of the scrotum and pubis, and in the female 

 upon the labium. The crural goes beneath Poupart's liga- 

 ment, pierces the sheath of the femoral vessels, sending 

 some filaments in company with the artery, passes through 

 the fascia lata, and supplies the integuments upon the front 

 of the thigh as far as its middle. 



The terminal branches of the lumbar plexus are the ante- 

 rior crural, obturator, and lumbo-sacral. 



The anterior crural (or femoral nerve) comes from the 



