Charles Eussell Bardeen 213 



region of emergence, 47 out of 121 instances, 38.9;^, see Fig. Y), or 

 in the vicinity of the femoral nerve (middle region of emergence, 55 

 instances, -15.5^', see Fig. II), or near the pubic crest (median region, 

 19 instances, 15.6^, see Fig. IV. A.). The crural nerve may pass to the 

 leg in corresponding regions (lateral emergence, 27 out of 133 instances, 

 20.3;?^, see Fig. I. C), middle emergence, 81 instances, 60. 9^ see 

 Fig. I. A, median emergence, 25 instances, 18. 8^ see Fig. III. E.). 



When the genital nerve passes into the path of the inguinal near the 

 anterior superior spine, it assumes many of the characteristics of the 

 inguinal nerve. The inguinal nerve may take a course to the extreme 

 .ventral limit of the iliac crest before passing into the abdominal mus- 

 culature. Between an inguinal nerve of this type and a genital nerve 

 emerging in a lateral region, only an artificial distinction can be drawn. 

 As the line of demarkation between the two, I have taken the anterior 

 superior spine. 



The crural nerve, when it emerges laterally, sIioavs a tendency to 

 become more or less closely uiiited to the lateral cutaneous nerve of the 

 thigh. Occasionally the crural nerve arises as a branch of the lateral 

 cutaneous (9 instances out of 287, ,3.1^). In one instance only have I 

 seen a genital nerve arising as a branch of the lateral cutaneous nerve 

 of the thigh. 



Origin of the Lateral Cutaxeous Nerve of the Thigh. See 

 Tohle XIV. — In connection with the border-nerves it may be of interest 

 to consider briefly the origin of the lateral cutaneous nerve in connection 

 with the various types of distribution of the border-nerves. In the 

 more " anterior " types of border-nerves, it Avill be noted that the lateral 

 cutaneous nerve springs most frequently from the 21st and 22nd spinal 

 nerves, while in more posterior types it springs from the (21st), 22nd 

 and 23rd, or from the main trunk of the femoral nerve. This associa- 

 tion is not, however, a constant one. 



General Conclusions. 



Variation in the abdominal and border-nerves may be due either to 

 local conditions, which affect merely the nerves derived from a given 

 spinal segment and their immediate neighbors, or it may be due to 

 conditions which affect the whole distal region of the spinal axis, and 

 the position of the limb relative to the axis. Eace, sex and side of body 

 seem to have no specific influence in determining variation of either sort. 



Variation in the abdominal uerves anterior to the twelfth intercostal 



