( 'U8 ) 



At jn'eseiit, guided l)y some new (wperimeiils in ihis uiattei', we 

 intend to make an endeavour towards coiistrucliiig our former results 

 provisorilv into a w lioI<', in ordei- to l)riim- tlie facts, found by means 

 of plivsiologieal researciies, into accordance witii the anatomical records 

 of the peripherical skin-innervalion of the trunk. 



We know hnl little with certainty ahont the topography and the 

 exact form of tiie different truidvdermatomata in man. Our knowledge 

 of both, such as it is, is due for the greater part to a more just 

 evaluation of the skin-iunervation of the nervi intercostales ^). 



It is evident however, that in the physiological experiment the 

 anatomical proportions will ha\e to lind llieir expression on the 

 ]>eriphery, and to all i)rol»ability oiii' fh'rmalomata, detei-miiu^d by 

 physiologic methods, will be proved to be wholly identical with the 

 extension-areas of the skinbi-anches of the nervi intercostales. 



According to our l)eiief, on dogs Ihis supposition has been even 

 proved alivady by our experiments. Kor Ity means of a careful 

 examination of a series of central ai'cas, it has been made clear 

 that the diiferences in shape, manifesting themselves by shortenings 

 or interruptions, may all be i-eli-aced lo anatomical proportions. 



The division of I he i]iteri-u|)led central area into a dorsal and 

 a ventral paiM, follows almost directly from the anatomy of the 

 intercostal nerve, whose skinbrauches consist in a posterior and an 

 anterior, respectively a dorsal and a latero-venti-al branch. The place 

 where the central area generally sulfei-s interrui)tio]i, or where in 

 favorable cases on the contiary it is found to be broadest (the lateral 

 part therefore of our trunk-dermatoma) corres})onds to the skin-area 

 of the rami cutanei laterales of this nerve. 



In this way. foi' the physiologist too, the central area is divided 

 into three individually ditferent parts, form and function of each of 

 which ought to be ti-eated separately. For a knowledge of both is 

 necessary in order to understand the significance of the dermatomata 

 on the extremities. 



The dorsal pai't of the central area is slia})ed like a truncated 

 triangle, whose basis is situated against the mid-dorsal line. Its apex 

 approaches the lateral line. Het ween the latter and the mid-doi'sal 

 line a line may be ti'aced from the doi'sal bordei- of the axilla to 

 the fossa inguinalis. 



It has become evident already from our former communications that 

 in favorable cases the dorsal central area towards the mid-dorsal 

 line possesses almost the same breadth as the whole dermatoma. 



1) BoLK. Een en ander over segnientaal-analoniie etc. N. T. v. Clenee.skunde 

 1897, Vol. 11, N". 10. 



