Correlation between musculoskeletal structure of the hand and primate locomotion: Morphometric and mechanical analysis in prehension using the cross- and triple-ratios
Journal article, 2020

Biometric ratios of the relative length of the rays in the hand have been analyzed between primate species in the light of their hand function or phylogeny. However, how relative lengths among phalanges are mechanically linked to the grasping function of primates with different locomotor behaviors remains unclear. To clarify this, we calculated cross and triple-ratios, which are related to the torque distribution, and the torque generation mode at different joint angles using the lengths of the phalanges and metacarpal bones in 52 primates belonging to 25 species. The torque exerted on the finger joint and traction force of the flexor tendons necessary for a cylindrical grip and a suspensory hand posture were calculated using the moment arm of flexor tendons measured on magnetic resonance images, and were compared among Hylobates spp., Ateles sp., and Papio hamadryas. Finally, the torques calculated from the model were validated by a mechanical study detecting the force exerted on the phalanx by pulling the digital flexor muscles during suspension in these three species. Canonical discriminant analysis of cross and triple-ratios classified primates almost in accordance with their current classification based on locomotor behavior. The traction force was markedly reduced with flexion of the MCP joint parallel to the torque in brachiating primates; this was notably lower in the terrestrial quadrupedal primates than in the arboreal primates at mild flexion. Our mechanical study supported these features in the torque and traction force generation efficiencies. Our results suggest that suspensory or terrestrial quadrupedal primates have hand structures that can exert more torque at a suspensory posture, or palmigrade and digitigrade locomotion, respectively. Furthermore, our study suggests availability of the cross and triple-ratios as one of the indicators to estimate the hand function from the skeletal structure.

Author

Toshihiro Tamagawa

Shiga University of Medical Science

Torbjörn Lundh

Chalmers, Mathematical Sciences, Applied Mathematics and Statistics

Kenji Shigetoshi

Shiga University of Medical Science

Norihisa Nitta

Shiga University of Medical Science

Noritoshi Ushio

Shiga University of Medical Science

Toshiro Inubushi

Shiga University of Medical Science

Akihiko Shiino

Shiga University of Medical Science

Anders Karlsson

Chalmers, Mathematical Sciences, Applied Mathematics and Statistics

Takayuki Inoue

Shimane University

Yutaka Mera

Shiga University of Medical Science

Kodai Hino

Shiga University of Medical Science

Masaru Komori

Shiga University of Medical Science

Shigehiro Morikawa

Shiga University of Medical Science

Shuji Sawajiri

Shiga University of Medical Science

Shigeyuki Naka

Shiga University of Medical Science

Satoru Honma

Kanazawa Medical University

Tomoko Kimura

Shiga University of Medical Science

Yasuhiro Uchimura

Shiga University of Medical Science

Shinji Imai

Shiga University of Medical Science

Naoko Egi

Primate Research Institute

Hiroki Otani

Shimane University

Jun Udagawa

Shiga University of Medical Science

PLoS ONE

1932-6203 (ISSN)

Vol. 15 05 1-29

Subject Categories

Other Medical Sciences not elsewhere specified

Other Biological Topics

Other Mathematics

Roots

Basic sciences

Areas of Advance

Life Science Engineering (2010-2018)

DOI

10.1371/journal.pone.0232397

PubMed

32365096

Related datasets

Primates supplementary materials [dataset]

URI: https://hdl.handle.net/10422/00012617

More information

Latest update

7/7/2020 8