Estimating thumb-index finger precision grip and manipulation potential in extant and fossil primates.

Bibliographic Collection: 
Publication Type: Journal Article
Authors: Feix, Thomas; Kivell, Tracy L; Pouydebat, Emmanuelle; Dollar, Aaron M
Year of Publication: 2015
Journal: J R Soc Interface
Volume: 12
Issue: 106
Date Published: 2015 May 6
Publication Language: eng
ISSN: 1742-5662
Keywords: Animals, Computer Simulation, Finger Joint, Fingers, Fossils, Hand Strength, Models, Biological, Motor Skills, Primates, Range of Motion, Articular

Primates, and particularly humans, are characterized by superior manual dexterity compared with other mammals. However, drawing the biomechanical link between hand morphology/behaviour and functional capabilities in non-human primates and fossil taxa has been challenging. We present a kinematic model of thumb-index precision grip and manipulative movement based on bony hand morphology in a broad sample of extant primates and fossil hominins. The model reveals that both joint mobility and digit proportions (scaled to hand size) are critical for determining precision grip and manipulation potential, but that having either a long thumb or great joint mobility alone does not necessarily yield high precision manipulation. The results suggest even the oldest available fossil hominins may have shared comparable precision grip manipulation with modern humans. In particular, the predicted human-like precision manipulation of Australopithecus afarensis, approximately one million years before the first stone tools, supports controversial archaeological evidence of tool-use in this taxon.

DOI: 10.1098/rsif.2015.0176
Alternate Journal: J R Soc Interface