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

Figure 1

(a) Dissection of a Pan troglodytes showing a pectoralis abdominis muscle. Pm (pectoralis minor), Pa (pectoralis abdominis), and LD (latissimus dorsi). (b) Dissection of a Pan troglodytes. We can see a deep supernumerary fascicle. Pm (pectoralis minor) and PMdf (pectoralis major deep fascicle). (c) Superficial dissection of the pectoralis major of a Pan paniscus. PMpc (pectoralis major pars clavicularis), PMpsc (pectoralis major pars sternocostalis), and PMpa (pectoralis major pars abdominis). (d) Dissection of a Pan paniscus. The pectoralis major has been moved to one side to show a deep supernumerary fascicle. PM (pectoralis major) and PMdf (pectoralis major deep fascicle).

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