304 



PHYSIOLOGY 



CHAP. 



literature (Thorburn, Kocher, Gowers, Starr, Edinger, Leyden, 

 Goldscheider, Striimpell, Jacob, etc.) a series of observations on 

 the segmental innervation of muscle which agree with the fore- 

 going experimental and morphological facts. 



The main defect of Kocher's diagram, and also of that suggested 

 by the American neurologist Allen Starr, is in the metameric 



Fio. 180. Metameric distribution or transverse segmentation of cutaneous areas of sensibility of 

 human body, drawn with the limbs in the position of their embryonic growth. (Diagram con- 

 structed by Luciani from Bolk's data.) The series of dermatomes which successively correspond 

 'to the cervical, lumbar, and sacral roots is indicated by different degrees of shading. 



division of the limbs. Without giving sufficient attention to the 

 special character of the embryological development of the limbs, 

 they Starr more particularly represented the dermatomes as 

 running from the vertebral column to the limbs in uninterrupted 

 zones, narrow in the middle and somewhat expanded at the ends. 

 Bolk's schema, on the contrary, corresponds perfectly with our 

 knowledge of the embryological development of the limbs. The 

 arrangement of the dermatomes in the upper limb (Fig. 180) is in 

 the following order in the cranio-caudal direction : shoulder, outer 



