DEVELOPMENT OF THE LIMBS, BODY-WALL AND BACK 



IN MAN. 



CHARLES RUSSELL BARDEEN, M. D. AND WARREN HARMON LEWIS, M. D. 



From the. Anatomical Laboratory of the Johns Hopkins University , Baltimore^ Md. 



With 9 Plates and 27 Text Figures. 



The purpose of the following paper is a description of various typical 

 stages in the development of the back, the limbs, and the body-wall 

 in man. The work is based primarily upon reconstructions, according 

 to the method of Born,' of parts of five human embryos; it has been 

 extended and controlled by a study of the external form and of serial 

 sections of several other human embryos. Dr. Lewis has devoted special 

 study to the formation of the arm, Dr. Bardeen to that of the leg, the 

 body-wall and the back. 



In the accompanying table a list is given of the embryos utilized. 

 Those marked with an asterisk have been reconstructed. 



We shall consider the early stages in the development of the limbs, the 

 body-wall and the back, first, from the point of view of the external 

 form and, secondly, from that of internal structural ditferentiation. 



I. External Form. 



The external form of the embryos we have used has been compared 

 with that of embryos of a corresponding stage of development pictured 

 in the His Atlas.^ Figs. 1-15, on pages 3 to 9 represent a series of 

 embryos belonging some to the Mall collection and some to the His 

 collection. The general relation of the limbs and body-wall in embryos 

 between two and seven weeks of age,"* and between 2.1 and 20 mm. in 

 length, are here represented by simple outline diagrams, based in part 

 upon published drawings and in part upon photographs and upon 



1 See Bardeen : Wax plate reconstruction according to tlie method of Born as 

 utilized in the Anatomical Laboratory of the Johns Hopkins University. The Johns 

 Hopkins Bulletin, April-May-June, 1901. 



-Anatomic menschlicher Embryonen, Leipzig, 188.5. 



3 The ages given are for the most part only roughly approximate. 

 1 



