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BioMed Research International
Volume 2018, Article ID 9404508, 12 pages
Research Article

Inter- and Intraspecific Variations in the Pectoral Muscles of Common Chimpanzees (Pan troglodytes), Bonobos (Pan paniscus), and Humans (Homo sapiens)

1Unit of Human Anatomy and Embryology, University of Barcelona, C/Casanova 143, 08036 Barcelona, Spain
2Animal Postcranial Evolution (APE) Lab, Skeletal Biology Research Centre, School of Anthropology and Conservation, University of Kent, Canterbury CT2 7NR, UK
3Department of Biology, FFCLRP, University of São Paulo, Avenida Bandeirantes 3900, Ribeirão Preto, SP, Brazil
4Department of Anatomy and Radiology, University of Valladolid, C/Ramón y Cajal 7, 47005 Valladolid, Spain
5Department of Anatomy, Howard University College of Medicine, Washington, DC 20059, USA

Correspondence should be addressed to J. M. Potau; ude.bu@uatopj

Received 27 July 2017; Revised 11 December 2017; Accepted 26 December 2017; Published 21 January 2018

Academic Editor: Ayhan Cömert

Copyright © 2018 J. M. Potau et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We have analyzed anatomic variations in the pectoralis major and pectoralis minor muscles of common chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) and compared them to anatomic variations in these muscles in humans (Homo sapiens). We have macroscopically dissected these muscles in six adult Pan troglodytes, five Pan paniscus of ages ranging from fetus to adult, and five adult Homo sapiens. Although Pan troglodytes are thought to lack a separate pectoralis abdominis muscle, we have identified this muscle in three of the Pan troglodytes; none of the Pan paniscus, however, had this muscle. We have also found deep supernumerary fascicles in the pectoralis major of two Pan troglodytes and all five Pan paniscus. In all six Pan troglodytes, the pectoralis minor was inserted at the supraspinatus tendon, while, in Pan paniscus and Homo sapiens, it was inserted at the coracoid process of the scapula. Some of the anatomic features and variations of these muscles in common chimpanzees and bonobos are similar to those found in humans, therefore enhancing our knowledge of primate comparative anatomy and evolution and also shedding light on several clinical issues.