@article{oai:shiga-med.repo.nii.ac.jp:00003494,
 author = {玉川, 俊広 and 重歳, 憲治 and 新田, 哲久 and 牛尾, 哲敏 and 犬伏, 俊郎 and 椎野, 顯彦 and 目良, 裕 and 日野, 広大 and 小森, 優 and 沢尻, 修司 and 仲, 成幸 and 本間, 智 and 木村, 智子 and 内村, 康寛 and 今井, 晋二 and 宇田川, 潤 and TAMAGAWA, Toshihiro and LUNDH, Torbjörn and SHIGETOSHI, Kenji and NITTA, Norihisa and USHIO, Noritoshi and INUBUSHI, Toshiro and SHIINO, Akihiko and KARLSSON, Anders and INOUE, Takayuki and MERA, Yutaka and HINO, Kodai and KOMORI, Masaru and SAWAJIRI, Shuji and NAKA, Shigeyuki and HONMA, Satoru and KIMURA, Tomoko and UCHIMURA, Yasuhiro and IMAI, Shinji and EGI, Naoko and OTANI, Hiroki and UDAGAWA, Jun},
 issue = {5},
 journal = {PloS ONE},
 month = {May},
 note = {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., Journal Article},
 title = {Correlation between musculoskeletal structure of the hand and primate locomotion: Morphometric and mechanical analysis in prehension using the cross- and triple-ratios.},
 volume = {15},
 year = {2020}
}