A Comparative Study of the A-B Ridge Count on the Palms of Mental Defectives and the General Population

Abstract

The finger-prints of mental defectives have been investigated by Bonnevie (1927), Poll (1935) and M⊘ller (1935). It was found that the frequency of whorls was less in the feeble-minded and imbeciles than in the general population but there was no correlation between intelligence quotients and quantitative values of patterns among defectives. Very little investigation has been carried out on the epidermal ridges of palms in mental defectives except in the case of mongoloid imbeciles, where Cummins (1939) and Workman (1939) have investigated the main patterns. Penrose (1949) has measured the angles subtended at triradius t by triradii a and b , and the present writer has counted the epidermal ridges between the a and b triradii.