Scanning electron microscopic study of dermatoglyphics in carpal tunnel syndrome

Abstract

The dermatoglyphics of the volar tip of the thumb and index finger of 20 patients in the first stage of carpal tunnel syndrome (CTS) without electromyographically detectable thenar impairment were examined by scanning electron microscopy with the aim of analysing its threedimensional features. In comparison with 20 healthy controls, only the central portion of the thumb and the central, medial and lateral portions of the index finger showed clear modifications. A low grade of hydrosis, confirmed by morphometrical measurements, was present in all pathological samples. Even the dermal ridges differed from the controls: in the pathological digits these were less flattened, more elevated and decreased in length, and the dermatoglyphics were less evident. The keratinocytes were identified on the dermal ridges in groups of 4–5 elements, with abundant exfoliation and numerous sweat pores which were irregular in size but had an increased diameter, probably due to compression of the autonomic fibers contained in the median nerve. To sum up, by using scanning electron microscopy, this study documented dermal alterations that occur in the thumb and index finger during the initial stages of CTS and that may be features of autonomic neuropathy.