On the distribution 

 of the cutaneous nerves on the dorsum of the human hand. 



By 

 H. St. John Brooks, M. D., 



Chief Demonstrator of Anatomy in the University of Dublin. 



(With pi. XXIII.) 



In the commencement of the present Session (1887 — 88), I was 

 led to investigate the Anatomy of the cutaneous nerves on the dorsum 

 of the hand by some passages I had met with in Létiévant's Treatise 

 on Sections of Nerves. In his preface, this Author states that after 

 section of a nerve -trunk, sensation is never completely lost in the 

 area of distribution of the divided nerve — a certain amount of sen- 

 sibility always persists. Létiévant explains this by the part played by 

 „anastomoses" and by „ébranlement des papilles à distance" x ). Com- 

 munications between nerves or „anastomoses" afford a very inadequate 

 explanation of many of the phenomena which this great neurotomist 

 describes in his book; and although the supposition that distant nerve- 

 endings can be affected by shock transmitted through the skin may 

 throw some light on the persistance of sensibility in the area of dis- 

 tribution of a divided nerve, it entirely fails to explain the fact that 

 the partial loss of sensation sometimes extends beyond the limits which 



*) Traité des Sections Nerveuses. Paris. 1873. „Malgré la section d'un nerf il 

 reste toujours, dans sa région, de la sensibilité, quand la division a porté sur un nerf 

 sensitif; . . ." Preface, p. XIV. „On ne saurait nier, certes, le rôle des anastomoses; 

 il convient même d'insister sur leur importance. Mais, chez l'homme, il y a, de plus, 

 une perception des sensations tactiles par ébranlement des papilles à distance". 

 Ibid. p. XVI. 



