Fingerprint maintenance, a new dermatoglyphic mechanism

Although dermatoglyphic structure has been mechanistically related to fingerprint formation, a separate mechanism for fingerprint maintenance must exist or prints would be lost by friction.

To test this prediction and study its operation.

Palmar and plantar prints were studied visually and by silicone rubber impressions after surface removal by abrasives, scalpel and adhesive stripping, using surface staining to stage surface loss.

All depths and methods of surface removal left the print ridges intact visually and in silicone rubber impressions. When abrasion was applied only to ridge surfaces, keratinocytes were lost concomitantly in the troughs between them, leaving ridge structure intact. When palmar or plantar stratum corneum was cleaved or peeled apart, the separated layer followed the undulating ridges and troughs, thus maintaining the normal print pattern.

A new mechanism of fingerprint maintenance was predicted theoretically and confirmed experimentally. It is achieved by an organization of the print corneum which ensures its continuous separation over the whole of the undulating print surface, even when friction is applied only to the tips of the ridges; the preferred route of separation of print keratinocytes runs up and down the print ridges and troughs and thereby maintains them, and is presumably ordered by predominantly horizontal intercellular attachments between print keratinocytes. The reason print maintenance has been missed until now may be that dermatoglyphic researchers have little interest in fingerprint disguise, while those who are interested in disguise have little interest in research.