ORGANIZATION OF TACTILE DERMATOMES, C1 THROUGH L4, IN CAT

Abstract

Dermatomes C1 through L4 were defined in the cat by electrically recording, in isolated dorsal root filaments, the afferent impulses initiated by mechanical displacement of shortened hairs. The results, added to those of Kuhn (Jour. Neurophysiol., 1953), complete the mapping of the dermatomes of this animal. For each filament a continuous area of skin was defined, consisting of a central area yielding maximal potentials and a fringe area producing weaker discharges. Each dermatome was determined by combining the results for all filaments of the related root. Extensive overlap was found for adjacent roots and filaments, but within each root a systematic shifting overlap from most rostral to most caudal filament was seen in the skin areas innervated, similar to the shifting overlap seen in successive whole dermatomes. Some dermatomes failed to reach either one or both (dorsal and ventral) midlines.