The relationship between total ridge count and pattern intensity index of digital dermatoglyphics

A mathematical relationship between total ridge count (TRC) and pattern intensity index (PII) is explored using data from a sample of 180 males and 213 females of Negroid origin from southwestern Haiti, West Indies. Linear regression of total ridge count on pattern intensity index gave good fit to data in males. In females the linear and quadratic regression models were less satisfactory probably due to the considerable overlap of ridge count distribution between loops and whorls. Two other measures which compare better than total ridge count are absolute ridge count and weighted total ridge count. Predictions of TRC from PII on the basis of regression estimates from Haitian data gave satisfactory results for Negroid and some Caucasoid populations but less satisfactory results for Mongoloid groups suggesting that the relationship might be different in different ethnic groups.