The morphology of the hypothenar radial arch: a study of hypothenar patterns in the Faroe Islands population.
Hypothenar patterns of 283 male and 320 female Faroe Islanders were classified according to the topological system of Penrose and Loesch (1970). Radial arches, individually specified according to their associated A-line configurations, were present at high frequencies (over 5.6%) in individuals of both sexes. Radial arches were about five times more frequent on right hands than on left. The occurrence of two main A-line types reported by Grace (1975), with a predominance of type 2 in Europeans, was confirmed. The contralateral patterns most frequently associated with radial arches were central loops and open fields. A developmental model is proposed, based on observation of the present study and the embryological studies of Cummins (1929). The contralateral patterns are taken as indicators of a developmental sequence of pattern formation from central or carpal loop to open field in which the radial arch can be considered an integral part. It is proposed that the configuration of ridges reflects the morphology and state of regression of the proximal hypothenar pad at the time of ridge differentiation and that the radial arch is formed at a transient phase during the loop to open field sequence. A suggestion, which needs confirmation from further population studies, that there may be a statistical association between the occurrence of the radial arch phenotype and absence of triradius c, also with unusual frequencies of digital patterns, has been raised by the present results.
D003878:Dermatoglyphics; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D012737:Sex Factors; D006113:United Kingdom