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. PotauEmail author
  • 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.


  1. Aiello, L., & Dean, C. (1990). An introduction to human evolutionary anatomy. London: Academic Press.Google Scholar
  2. Alpert, S. W., Pink, M. M., Jobe, F. W., McMahon, P. J., & Mathiyakom, W. (2000). Electromyographic analysis of deltoid and rotator cuff function under varying loads and speeds. Journal of Shoulder and Elbow Surgery, 9, 47–58.PubMedCrossRefGoogle Scholar
  3. Ashton, E. H., & Oxnard, C. E. (1963). The musculature of the primate shoulder. Transactions of the Zoological Society of London, 29, 553–650.Google Scholar
  4. Ashton, E. H., & Oxnard, C. E. (1964). Locomotor patterns in primates. Proceedings of the Zoological Society of London, 143, 1–28.Google Scholar
  5. Bartolozzi, A. R., Andreychik, D., & Ahmad, S. (1994). Determinants of outcome in the treatment of rotator cuff disease. Clinical Orthopaedics and Related Research, 308, 90–97.PubMedGoogle Scholar
  6. Basmajian, J. V., & de Luca, C. J. (1985). Muscles alive. Their functions revealed by electromyography. Baltimore: Williams & Wilkins.Google Scholar
  7. Bigliani, L. U., & Levine, W. N. (1997). Subacromial impingement syndrome. Journal of Bone & Joint Surgery (American Volume), 79, 1854–1868.Google Scholar
  8. Brox, J. I., Staff, P. H., Ljunggren, A. E., & Brevik, J. I. (1993). Arthroscopic surgery compared with supervised exercises in patients with rotator cuff disease (stage II impingement syndrome). British Medical Journal, 307, 899–903.PubMedCrossRefGoogle Scholar
  9. Chen, S. K., Simonian, P. T., Wickiewicz, T. L., Otis, J. C., & Warren, R. F. (1999). Radiographic evaluation of glenohumeral kinematics: a muscle fatigue model. Journal of Shoulder and Elbow Surgery, 8, 49–52.PubMedCrossRefGoogle Scholar
  10. Ciochon, R. L., & Corruccini, R. S. (1977). The coraco-acromial ligament and projection index in man and other anthropoid primates. Journal of Anatomy, 124, 627–632.PubMedGoogle Scholar
  11. Fleagle, J. G., Stern, J. T., Jungers, W. L., Susman, R. L., Vangor, A. K., & Wells, J. P. (1981). Climbing: a biomechanical link with brachiation and bipedalism. Symposia of the Zoological Society of London, 48, 359–373.Google Scholar
  12. Halder, A. M., Zhao, K. D., Odriscoll, S. W., Morrey, B. F., & An, K. N. (2001). Dynamic contributions to superior shoulder stability. Journal of Orthopaedic Research, 19, 206–212.PubMedCrossRefGoogle Scholar
  13. Hashimoto, T., Nobuhara, K., & Hamada, T. (2003). Pathologic evidence of degeneration as a primary cause of rotator cuff tear. Clinical Orthopaedics and Related Research, 415, 111–120.PubMedCrossRefGoogle Scholar
  14. Hawkins, R. J., & Dunlop, R. (1995). Nonoperative treatment of rotator cuff tears. Clinical Orthopaedics and Related Research, 321, 178–188.PubMedGoogle Scholar
  15. Inman, V. T., Saunders, J. B., & Abbott, L. C. (1944). Observations on the function of the shoulder joint. Journal of Bone & Joint Surgery (American Volume), 26, 1–30.Google Scholar
  16. Ishida, H., Kumakura, H., & Kondo, S. (1985). Primate bipedalism and quadrupedalism: comparative electromyography. In S. Kondo (Ed.), Primate morphophysiology, locomotor analyses and human bipedalism (pp. 59–79). Tokyo: University of Tokyo Press.Google Scholar
  17. Jih-Yang, K., Chung, H., Wei-Jen, C., Chin-En, C., Sung-Hsiung, C., & Ching-Jen, W. (2006). Pathogenesis of partial tear of the rotator cuff: A clinical and pathologic study. Journal of Shoulder and Elbow Surgery, 15, 271–278.CrossRefGoogle Scholar
  18. Kronberg, M., Nemeth, G., & Brostrom, L. A. (1990). Muscle activity and coordination in the normal shoulder. An electromyographic study. Clinical Orthopaedics and Related Research, 257, 76–85.Google Scholar
  19. Larson, S. G. (1993). Functional morphology of the shoulder in primates. In: Gebo, D. L. (Ed.), Postcranial adaptation in nonhuman primates (pp. 45–69).DeKalb, IL: Northern Illinois University Press.Google Scholar
  20. Larson, S. G., & Stern, J. T. (1986). EMG of scapulohumeral muscles in the chimpanzee during reaching and “arboreal” locomotion. American Journal of Anatomy, 176, 171–190.PubMedCrossRefGoogle Scholar
  21. Larson, S. G., & Stern, J. V. (1987). EMG of chimpanzee shoulder muscles during knucle-walking: problems of terrestrial locomotion in a suspensory adapted primate. Journal of Zoology London, 212, 629–655.CrossRefGoogle Scholar
  22. Leroux, J. L., Codine, P., Thomas, E., Pocholle, M., Mailhe, D., & Blotman, F. (1994). Isokinetic evaluation of rotational strengh in normal shoulders and shoulders with impingement syndrome. Clinical Orthopaedics and Related Research, 304, 108–115.PubMedGoogle Scholar
  23. Lindblom, K. (1939). On the pathogenesis of ruptures of the tendon aponeurosis of the shoulder joint. Acta Radiologica, 20, 563–577.CrossRefGoogle Scholar
  24. Lohr, J. F., & Uhthoff, H. K. (1990). The microvascular pattern of the supraspinatus tendon. Clinical Orthopaedics and Related Research, 254, 35–38.PubMedGoogle Scholar
  25. Ludewig, P. M., & Cook, T. M. (2002). Translations of the humerus in persons with shoulder impingement symptoms. Journal of Orthopaedic & Sports Physical Therapy, 32, 248–259.Google Scholar
  26. McMahon, P. J., Debski, R. E., Thompson, W. O., Warner, J. J., Fu, F. H., & Woo, S. L. (1995). Shoulder muscle force and tendon excursions during glenohumeral abduction in the scapular plane. Journal of Shoulder and Elbow Surgery, 4, 199–208.PubMedCrossRefGoogle Scholar
  27. Michener, L. A., McClure, P. W., & Karduna, A. R. (2003). Anatomical and biomechanical mechanisms of subacromial impingement syndrome. Clinical Biomechanics, 18, 369–379.PubMedCrossRefGoogle Scholar
  28. Neer, C. S. (1972). Anterior acromioplasty for the chronic impingement syndrome in the shoulder: a preliminary report. Journal of Bone & Joint Surgery (American Volume), 54, 41–50.Google Scholar
  29. Oxnard, C. E. (1963). Locomotor adaptation in the primitive forelimb. Symposium of the Zoological Society of London, 10, 165–182.Google Scholar
  30. Oxnard, C. E. (1967). The functional morphology of the primate shoulder as revealed by comparative anatomical, osteometric and discriminant function techniques. American Journal of Physical Anthropology, 26, 219–240.CrossRefGoogle Scholar
  31. Oxnard, C. E. (1969). Evolution of the human shoulder: some possible pathways. American Journal of Physical Anthropology, 30, 319–332.PubMedCrossRefGoogle Scholar
  32. Payne, L. Z., Deng, X. H., Craig, E. V., Torzilli, P. A., & Warren, R. F. (1997). The combined dynamic and static contributions to subacromial impingement. A biomechanical analysis. American Journal of Sports Medicine, 25, 801–808.Google Scholar
  33. Perry, J., Barnes, G., & Merson, J. (1989). Normal electromyographic values of six shoulder muscles during free motion. Orthopaedic Transactions, 13, 322–323.Google Scholar
  34. Poppen, N. K., & Walker, P. S. (1976). Normal and abnormal motion of the shoulder. Journal of Bone & Joint Surgery (American Volume), 58, 195–201.Google Scholar
  35. Prost, J. H. (1980). Origin of bipedalism. American Journal of Physical Anthropology, 52, 175–189.PubMedCrossRefGoogle Scholar
  36. Rathburn, J. B., & Macnab, I. (1970). The microvascular pattern of the rotator cuff. Journal of Bone & Joint Surgery (American Volume), 52, 540–553.Google Scholar
  37. Reddy, A. S., Mohr, K. J., Pink, M. M., & Jobe, F. W. (2000). Electromyographic analysis of the deltoid and rotator cuff muscles in persons with subacromial impingement. Journal of Shoulder and Elbow Surgery, 9, 519–523.PubMedCrossRefGoogle Scholar
  38. Roberts, D. (1974). Structure and function of the primate scapula. In F. A. Jenkins (Ed.), Primate locomotion (pp. 171–200). New York: Academic Press.Google Scholar
  39. Schultz, A. H. (1961). Vertebral column and thorax. Primatologia, 4, 1–66.Google Scholar
  40. Senut, B. (1988).Climbing as a crucial preadaptation for human bipedalism. International Journal of Skeletal Research, 14, 35–44.Google Scholar
  41. Stern, J. T. (1975). Before bipedality. Yearbook of Physical Anthropology, 19, 59–68.Google Scholar
  42. Stern, J. T., & Susman, R. L. (1981). Electromyography of the gluteal muscles in Hylobates, Pongo and Pan: implications for the evolution of hominid bipedality. American Journal of Physical Anthropology, 55, 153–166.CrossRefGoogle Scholar
  43. Thorpe, S. K. S., Holder, R. L., & Crompton, R. H. (2007). Origin of human bipedalism as an adaptation for locomotion on flexible branches. Science, 316, 1328–1331.PubMedCrossRefGoogle Scholar
  44. Tuttle, R. H. (1969). Knuckle-walking and the problem of human origins. Science, 166, 953–961.PubMedCrossRefGoogle Scholar
  45. Tuttle, R. H. (1974). Darwin’s apes, dental apes, and the descent of man: normal science in evolutionary anthropology. Current Anthropology, 15, 389–398.CrossRefGoogle Scholar
  46. Tuttle, R. H., & Basmajian, J. V. (1978). Electromyography of pongid shoulder muscles. Part II, deltoid, rhomboid, and “rotator cuff.” American Journal of Physical Anthropology, 49, 47–56.Google Scholar
  47. Warner, J. J., Micheli, L. J., Arslanian, L. E., Kennedy, J., & Kennedy, R. (1990). Patterns of flexibility, laxity and strength in normal shoulders and shoulders with instability and impingement. American Journal of Sports Medicine, 18, 366–375.PubMedCrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2009

Authors and Affiliations

  • J. M. Potau
    • 1
    Email author
  • 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

Personalised recommendations