Characteristically the skin of hands and feet shows a particular morphological design called dactylogram. This pattern is typically on the thick skin of the digits, the palm of the hands and the soles of the feet, and its properties have a leading role in human identification. The changes that take place on the volar side of the thumb due to the aging process have not yet been described. It is for this reason that the objective of the present work is to show the variation of the biostructure on the skin of the volar side of the first digit of the right hand in elderly individuals. For this research, skin samples of the right thumb from elderly Chilean subjects of both sexes were used. These samples underwent histological studies with H & E, Mallory ́s trichrome, Sirio of Junqueira Red, PAS Reaction and Orcein staining. The observation and records were made with Zeiss Axiostar Plus Microscope, a Canon PowerShot A 640 camera, and Image Tool 3.0 software UTHSCSA, 2002. The results showed significant changes on the epidermis thickness, in the basement membrane morphology, in the shape and quantity of blood vessels, the distribution and arrangement pattern of the collagen and elastic fibers, and in the increase of tactile corpuscles. These changes confirm the existence of significant histological changes due to the aging process, which could be decisive in the gradual fading of the morphological characteristics of the dactylogram, making it difficult to observe, demonstrate and record the dactylogram on individuals of advanced age which reduces the possibility of identification of those individuals, leading to possible medical-legal consequences.
KEY WORDS: Dactylogram; Human identification; Legal medicine; Aging of the skin; Histology of the skin; Fingerprint.