Muscle dimensions in the chimpanzee hand

Naomichi Ogihara, Takeo Kunai, Masato Nakatsukasa

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


We dissected the forearms and hands of a female chimpanzee and systematically recorded mass, fiber length, and physiological cross-sectional area (PCSA) of all muscles including those of intrinsic muscles that have not been reported previously. The consistency of our measurements was confirmed by comparison with the published data on chimpanzees. Comparisons of the hand musculature of the measured chimpanzee with corresponding published human data indicated that the chimpanzee has relatively larger forearm flexors but smaller thenar eminence muscles, as observed in previous studies. The interosseous muscles were also confirmed to be relatively larger in the chimpanzee. However, a new finding was that relative PCSA, which reflects a muscle's capacity to generate force, might have increased slightly in humans as a result of relatively shorter muscle fiber length. This suggests that the human intrinsic muscle architecture is relatively more adapted to dexterous manipulative functions. Shortening of the metacarpals and the intervening interosseous muscles might accordingly be a prerequisite for the evolution of human precision-grip capabilities.

Original languageEnglish
Pages (from-to)275-280
Number of pages6
Issue number4
Publication statusPublished - 2005 Oct


  • Biomechanics
  • Finger
  • Manipulation
  • Pan
  • Thumb

ASJC Scopus subject areas

  • Animal Science and Zoology


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