Charles Eussell Bardeen 311 



communication from tiie 30th. The iliac nerve was derived from the 

 31st spinal nerve in 198 instances, 70.4^. Tlie mode of origin of the 

 iliac nerve is indicated in the table. Most commonly (331 instances, 

 86;^) it arises as a branch from the hypogastric nerve as this passes near 

 the iliac crest. In 43 instances, 15.3^', it arose as a branch of the main 

 ventral trunk of the ■30th spinal nerve. Less frequently (31 instances, 

 7.5^) it passed as a separate trunk from the region of the spinal axis 

 (dorsal origin) to the crest of the ilium. In only 33 instances, 8.3^ 

 was an iliac nerve found to arise from the inguinal. The term ilio- 

 inguinal should be restricted to nerves of this character, which are com- 

 paratively rare. Two iliac branches are not infrequent. 



Okigin of the Inguinal Neeve. — The inguinal nerve in the great 

 majority of instances arises from the 31st spinal nerve (358 instances, 

 89.8;?;). In nearly half of these instances (110) fibres were also derived 

 through a proximal communicating branch from the 30th spinal nerve. 

 In 10 instances, 3.5^, it arose from the 30th spinal nerve, and in 19 

 instances, 6.6^, the place of the inguinal nerve was taken by the genital 

 branch of the genito-crural. Most commonly (334 instances, 78^) the 

 inguinal nerve takes a course to the iliac crest separate from that of 

 the hypogastric. Not infrequently (36 instances, 13.5;^), however, these 

 two nerves pass in a common trunk as far as the iliac crest, and infre- 

 quently (8 instances, 3.8;^) they pass in a common trunk to the region of 

 the external ring, Avhence the hypogastric branch turns up over the 

 abdomen, while the inguinal nerve takes its way to the region where 

 scrotum and leg adjoin. 



Okigin and Course of the Genito-ceueal Keeves. See Table 

 XIII. — So great is the variety in the distribution of the genito-crural 

 nerves, it would be necessary to describe nearly every subject exam- 

 ined in order to record the many different courses taken by these nerves. 

 The main trunks of the abdominal nerves are kept fairly constant in 

 distribution, owing to their relation to the rectus muscle. The hypo- 

 gastric and inguinal nerves are kept within moderate bounds, owing to 

 their course in channels between the transversalis and internal oblique 

 muscles, and between the latter and the flat tendon of the external 

 oblique, channels that are limited distally by the crest of the ilium and 

 by Poupart's ligament. Not infrequently the inguinal nerve courses 

 for some distance between the abdominal fascia and the transversalis 

 muscle before piercing the latter and entering the channel offered be- 

 tween it and the internal oblique muscle. In the region of its attach- 



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