Bardeen, Variations in the Lnmbar Plexus. 1 99 



The most notable thing brought out in this table is the 

 great variety in the distribution of those spinal nerves which 

 supply the cutaneous nerves distributed to the regions where 

 the thigh and abdomen meet. 



There is nothing especially remarkable about the distribu- 

 tion of the eleventh thoracic nerve. It is interesting to note how- 

 ever that in one of the cases in which there was a communica- 

 tion between the eleventh and twelfth thoracic nerves, a thir- 

 teenth thoracic nerve was found. It is to be noted that the 

 ileo-hypogastric nerve arises in over 40 ^r of the plexuses direct- 

 ly from the twelfth thoracic. In the text-books it is said to 

 arise from the first lumbar nerve. The first lumbar nerve is 

 essentially the source of supply of the ileo-inguinal nerve. In 

 a little over 25^ of the specimens it alone gives rise to the 

 ileo-hypogastric. It is intimately connected with the genito- 

 crural and seems to be the main source of cutaneous supply to 

 the border-land between the thigh, the genitalia and the ab- 

 domen. 



While the main strength of the second lumbar is given to 

 the obturator and the anterior crural nerves, either directly or 

 through the communicating branch, it also contributes largely 

 to the external cutaneous, and to the genito-crural. The great 

 variety of the paths by which this nerve is distributed is re- 

 markable. Of the third lumbar nothing special need be said. 

 The fourth lumbar as a rule is divided between the two great 

 nerves of the lumbar plexus, and the sacral plexus. In thir- 

 teen per cent, of these plexuses it was distributed wholly to the 

 former nerves. The fifth nerve as a rule belongs wholly to the 

 sacral plexus. 



For the sake of simplicity no account has been taken in 

 these tables of the small muscular nerves derived directly from 

 the spinal nerves, of the relative size of the nerves, or of the 

 peripheral distribution of the main nerve trunks. 



