The Classification Formula and Extensions
The classification formula
At this point it is necessary to mention that when prints are classified, markings are indicated at the bottom of each finger block to reflect the type. The following symbols are used:
● Under the index fingers the appropriate capital letters should be placed for every pattern except the ulnar loop.
● Under all other fingers, the appropriate small letter should be placed for every pattern except the ulnar loop and the whorl as follows:
| Arch | a |
| Tented Arch | t |
| Radial Loop | r |
● Ulnar loops in any finger are designated by a diagonal line slanting in the direction of the loop.
● Whorls in any finger are designated by the letter "W". The classification formula may be composed of the following divisions:
| 1. Primary | 4. Major |
| 2. Secondary | 5. Final |
| 3. Subsecondary | 6. Key |
The positions in the classification line for these divisions when completely applied are as illustrated: