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Nachdruck verboten. 



Costo-Vertel)ial Variation in Man. 



By Charles Russell Bakdeen, Associate in Anatomy, Johns Hopkins 

 University, Baltimore, Md. 



In connection with some studies I have been making of variations 

 in the distribution of the peripheral nerves, as revealed in the dis- 

 secting room of the Anatomical Laboratory, I have taken occasion to 

 examine critically the skeletal apparatus in a number of individuals. 

 Variations in the vertebral column and ribs occurred so frequently 

 that it has seemed to me a record of the conditions found might prove 

 of interest. 



The number of bodies studied was fifty-nine. Of these forty-four 

 (74,6 7o) were negroes and fifteen (25,4 7o) white subjects; forty-one, 

 (69,5 7o) were males and eighteen (30,5 7o) females. The results I have 

 arranged in the following table. 



The table is divided by a series of horizontal lines into a series 

 of parallel spaces, each of which represents a vertebra, designated 

 numerically at the left. Certain of these horizontal lines are made 

 heavy, so as to show the usual division of the vertebral column into 

 cervical, thoracic, lumbar, sacral and coccygeal regions. By a series 

 of heavy vertical lines, the table is divided into eight divisions. Each 

 of these represents a definite variety of vertebral column and is de- 

 signated by a letter placed at the head of the column. The first four 

 columns contain the records of those individuals in which there seemed 

 to be a tendency to a costo-vertebral reduction. They have, therefore, 

 been gathered into one group (Group I). The fifth column contains 

 the record of those bodies in which the vertebrae were found to be 

 "normal" in number and form Group II. The three columns at the 

 right record the conditions found in those instances in which there 

 seemed to be a tendency to increase in the length of the vertebral 

 column (Group III). 



It will be seen that in thirty instances (50,8 7o) the vertebral 

 column is to be looked upon as "normal". Of these 24 (80%) occurred 

 in negroes, 6 (20 7o) in white subjects; 28 (76,6 7o) ii males and 7 

 (23,4 7o) in females. 



In 23 (38 7o of the total number. Group I), there were evidences 

 of a tendency to a costo-vertebral reduction. In the simplest form 



