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

Figure 5

Main muscle variants observed in the present study. (a) Pectoralis abdominis. (b) Deep supernumerary fascicle in the pectoralis major. (c) Insertion of the pectoralis minor at the supraspinatus tendon. SCM (sternocleidomastoideus), LC (levator claviculae), T (trapezius), DEL (deltoideus), PM (pectoralis major), PA (pectoralis abdominis), SA (serratus anterior), OE (obliquus externus), BB (biceps brachii), TB (triceps brachii), BR (brachioradialis), Pm (pectoralis minor), PMSF (pectoralis major supernumerary fascicle), A (acromion), SUP (supraspinatus), SUPt (supraspinatus tendon), Pmt (pectoralis minor tendon), H (humerus), CP (coracoid process), SUB (subscapularis), TM (teres major), LDt (latissimus dorsi tendon), DE (dorsoepitrochlearis), CB (coracobrachialis), BBcb (biceps brachii caput breve), and BBcl (biceps brachii caput longum).

(a)

(b)

(c)