International Journal of Primatology

, Volume 30, Issue 5, pp 697–708 | Cite as

Quantitative Analysis of the Deltoid and Rotator Cuff Muscles in Humans and Great Apes

  • J. M. Potau
  • X. Bardina
  • N. Ciurana
  • D. Camprubí
  • J. F. Pastor
  • F. de Paz
  • M. Barbosa


The shoulder is one of the anatomic regions differentiating orthograde primates (gibbons, orangutans, gorillas, chimpanzees, bonobos, and humans) from the rest of the pronograde primates. Orthograde primates are characterized by a dorsal position of the scapula and a more lateral orientation of the glenoid cavity. This anatomic pattern, together with adaptations in related osteological structures and muscles, serves to facilitate the elevation of the upper extremity in the scapular plane. We quantified the proportions of the muscles comprising the principal functional and stabilizing components of the glenohumeral joint —deltoid, subscapularis, supraspinatus, infraspinatus, and teres minor— in 3 species of orthograde primates: Pongo pygmaeus, Pan troglodytes, and Homo sapiens. Our objective was to determine whether quantifiable differences in these muscles relate to the functional requirements of the types of locomotion used by these 3 species: suspension/vertical climbing, knuckle-walking, and bipedalism. We observed a close similarity between the proportional mass of these muscles in Homo sapiens and Pongo pygmaeus, whereas Pan troglodytes displayed a unique anatomic pattern, particularly in the subscapularis, which may be due to differences in how the glenohumeral joint is stabilized in a great ape knuckle-walker. Our findings may help explain the high incidence of subacromial impingement syndrome in humans.


deltoid glenohumeral joint great apes rotator cuff 



We thank the following for their support and collaboration: Manuel Martín, Sebastián Mateo, and Pau Rigol (Body Donation Service, University of Barcelona); María García and Eva María Ferrero (Department of Anatomy and Radiology, University of Valladolid); and Renee O'Brate.


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Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • J. M. Potau
    • 1
  • X. Bardina
    • 1
  • N. Ciurana
    • 1
  • D. Camprubí
    • 1
  • J. F. Pastor
    • 2
  • F. de Paz
    • 2
  • M. Barbosa
    • 2
  1. 1.Unit of Human Anatomy and EmbryologyUniversity of BarcelonaBarcelonaSpain
  2. 2.Department of Anatomy and RadiologyUniversity of ValladolidValladolidSpain

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