Comparative anatomical characteristics of the distal parts of bear and human limbs

BACKGROUND: The comparative morphology of the human and animal skeletons has been incompletely described in the forensic medical and anthropological literature. Moreover, bones of the distal parts of bear limbs are anatomically similar to those of humans. Together with some features of the bear’s skeleton, poor preservation, absence of claws, and incomplete remains, difficulties and errors may occur during identification.

AIM: To create an illustrative material describing morphological features important for the identification of each element of the distal parts of bear limbs in comparison with humans.

MATERIALS AND METHODS: Preparations of the distal parts of the right thoracic and right pelvic extremities of the bear were made using osteological materials. The missing talon phalanges of a bear and bones of a human hand and foot were taken from the institute collections. The International Veterinary Anatomical Nomenclature was used to describe the anatomical features of bear bones, and the latest recommendations of International Anatomical Terminology were considered for human bones.

RESULTS: Each bone of the bear’s hand and foot was described in comparison with a similar human bone. For greater versatility, descriptions were made in terms of the international zoological nomenclature. For all bones, except for distal sesamoid bones, high-quality photos are provided for aspects that are important for identification. Comparative anatomical analysis showed that the bones of the wrist differ to a greater extent, whereas all tarsal bones, which are part of the human foot, had analogs in the bear foot and had closer measurements. The articular surfaces of the heads of the metacarpals and metatarsals showed specific ridges articulating with the cutouts at the bases of the proximal phalanges of the fingers. In addition, the bear’s hand and foot contained numerous inset sesamoid bones and claw-like processes on the distal phalanges of the fingers.

CONCLUSION: Comparative anatomical analysis showed similarities in the structures of the bones of the hand and foot of a brown bear and a human caused by foot walking. Owing to the morphological similarity, bone identification can be difficult. The set of features described in the article, which are specific to bear bones, in combination with illustrative material will help in identifying bones more accurately, even for individual bones.