Charles Kussell Bardeen 209 



Eelative Distkibutiox oe the BoRDER-ISrERVES OX Each Side of 

 THE Body. See Table VII. — There is considerable variation in the 

 types of distribution exhibited by similar nerves on the two sides of the 

 same body. In Table VII the relation of the types of distribution of 

 the border-nerves on one side of the individual to those on the other 

 are given. Each numeral in the body of the table indicates the number 

 of instances in which the type of distribution indicated at the left of the 

 table was found associated with the type of distribution indicated at the 

 top of the column. Thus, in two instances, when Type I D. was found 

 on the right side, Type I C. was found on the left. The heavy figures 

 indicate that the type of distribution of the border-nerves was the same 

 on each side of the body in the number of individuals denoted by the 

 figure. Thus, Type I B. was found on each side of the body in two 

 individuals. It will be noted that while slight variations in type of 

 distribution is very common, marked variation is rare. 



Eelatiox of Variations in the Spinal Column to the Various 

 Types of Distribution of the Border-Nerves. See Table VIII. — 

 This table shows that a close relation exists between the development of 

 the spinal axis and the distribution of the border-nerves. Eeduction in 

 the spinal axis is marked in extreme cases by the loss of a thoracic, 

 lumbar or sacral vertebra. In less extreme instances there is a tendency 

 for the twelfth thoracic vertebra to assume the lumbar type, for the 

 fifth lumbar to assume the sacral type, and for the fifth sacral to 

 assume the coccygeal type. Although occasionally the twelfth rib 

 may be ill-developed witliout accompanying changes in the lumbar 

 and sacral vertebra, as a rule a rudimentary 12th rib indicates a ten- 

 dency to a shortening of the spinal axis, as outlined above. AYlien 

 the spinal axis is reduced, the hip bones are attached to the spinal axis 

 more anteriorly than is usual, although not necessarily to the 24th 

 vertebra. This anterior position of the posterior limb accounts for the 

 derivation of the border-nerves from a more anterior set of spinal nerves 

 than normal. Types I A., B., C, D., E., II and III A. and B. On the 

 other hand, types of border-nerves marked by a more distal origin than 

 normal (IV B. & V.), are characterized by the great frequency with 

 which they are associated with extension in the vertebral column, marked 

 in extreme cases by the addition of an extra thoracic, lumbar, or sacral 

 vertebra. 



Types of Lumbo-Sacral Plexus Associated with the Various 

 Types of Distribution of the Boeder-Nerves. See Table IX. — As 



