Peripheral cutaneous nerve distribution to the fingers.

Both sensory distribution charts and the unaffected side, are used as reference points in the assessment of cutaneous innervation. Sensory nerve conduction studies, in particular, often use comparison between sides. However, remarkable differences can be found between various sensory innervation maps, and no evidence was found in the literature for the assumption that the pattern of cutaneous sensory distribution of the peripheral nerves between the left and right limbs is symmetrical. The purpose of this study was to investigate variations in the sensory innervation of the fingers by means of a neurophysiological method, and to compare the results for the left and right hands. The subjects of this study were 31 young women. Percutaneous peripheral nerve stimulation was performed on the four nerve branches providing sensory innervation to the fingers, and action potentials were sought from the fingers by use of annular surface electrodes. Variations in the cutaneous innervation of the fingers between individuals often occurred and were found more frequently on the dorsal than the palmar aspect. The distribution of sensory innervation may even differ markedly between hands in the same individual. The cutaneous innervation of all peripheral nerves supplying the fingers may differ from the innervation patterns described in the various distribution charts. Prudence is called for when applying sensory distribution charts as absolute references for the assessment of cutaneous sensation in patients. Caution should also be applied when comparing one hand with the other when assessing the cutaneous innervation of the fingers.