Identification of decedents by restoring mummified fingerprints: Forensic dermatology in the investigation of mummy dermatoglyphics.

Fingerprints are created by elevations and depressions on the fingertip pads. Each person has their own unique fingerprints, which can be used in the identification of that individual when alive, during the immediate postmortem period, or even after the digits have become mummified. Mummification can occur naturally; it can be partial (such as localized to only the hands and feet), extensive, or complete. Obtaining fingerprints after the skin has become mummified can be attempted while the digits remain attached to the hand, but the digits may need to be removed from the hand, and the finger pads may also need to be separated from the underlying bone to secure an adequate fingerprint. The mummified tissue often needs to be rehydrated; numerous solutions have been used that increase the turgor of the digits, provide softening and pliability of the tissue, and enhance the details of the finger pad ridges. An aqueous solution of sodium carbonate (either combined with acetic acid or combined with 95% ethanol and distilled water) was found to be most effective for rehydration. Thereafter, various techniques can be attempted to obtain the fingerprint. These include the traditional method of inking and rolling of the finger or photographing the finger. Powders (such as aluminum powder, black fingerprint powder, white cornstarch-based powder, or fluorescent powder) can be used to enhance the ridge features; adhesive tape can be pressed against the powdered digit and the print pattern preserved by applying the adhesive tape to a clear transparency sheet. Molds (using modeling clay or silicone rubber) and casts (using plaster of paris, dental casting materials, or putty) of the digits can be created; either the molds or the casts or both can be photographed with or without prior application of fingerprint powder. Transillumination, using a fiber optic light source to illuminate the epidermis and underlying remaining dermis of a scraped and defleshed finger pad, can be used to demonstrate the finger ridge pattern when photographing the tip of the digit. Forensic dermatology can play an integral role in obtaining fingerprints from mummified digits, which can be successfully used for the identification of a decedent.