Muscle architecture of the upper limb in the orangutan

Motoharu Oishi, Naomichi Ogihara, Hideki Endo, Masao Asari

Research output: Contribution to journalArticlepeer-review

32 Citations (Scopus)


We dissected the left upper limb of a female orangutan and systematically recorded muscle mass, fascicle length, and physiological cross-sectional area (PCSA), in order to quantitatively clarify the unique muscle architecture of the upper limb of the orangutan. Comparisons of the musculature of the dissected orangutan with corresponding published chimpanzee data demonstrated that in the orangutan, the elbow flexors, notably M. brachioradialis, tend to exhibit greater PCSAs. Moreover, the digital II-V flexors in the forearm, such as M. flexor digitorum superficialis and M. flexor digitorum profundus, tend to have smaller PCSA as a result of their relatively longer fascicles. Thus, in the orangutan, the elbow flexors demonstrate a higher potential for force production, whereas the forearm muscles allow a greater range of wrist joint mobility. The differences in the force-generating capacity in the upper limb muscles of the two species might reflect functional specialization of muscle architecture in the upper limb of the orangutan for living in arboreal environments.

Original languageEnglish
Pages (from-to)204-209
Number of pages6
Issue number3
Publication statusPublished - 2008 Jul
Externally publishedYes


  • Locomotion
  • Muscle architecture
  • Pongo
  • Upper limb

ASJC Scopus subject areas

  • Animal Science and Zoology


Dive into the research topics of 'Muscle architecture of the upper limb in the orangutan'. Together they form a unique fingerprint.

Cite this