Three categories of whorls-ulnar oriented (Wu), radial oriented (Wr) and symmetrical whorls (Ws)-are recognized by the proportional representation of their two ridge counts (RC). In the Wu the radial RC is greater, in the Wr the ulnar RC is greater, and in the Ws the two RCs are equal. These three categories of whorls are distinguished from one another by their frequencies, their distribution on individual fingers, and their mean ridge counts. The differences between Wu, Wr and Ws are analogous to those observed between the three other pattern types, namely, the ulnar loops, radial loops and arches.
- ridge counts
- whorls classification