Fig. 1.

Raw fascicle length (cm) data scaled using individual group allometric exponents in instances where there was a significant relationship to body mass. In instances where this was not the case, raw fascicle length data are presented, although a direct comparison between the two forms of data cannot be made. (a) Shoulder rotators (M^0.27), (b) shoulder adductors (raw data), (c) shoulder abductors (M^0.20), (d) shoulder flexors (M^0.22), (e) shoulder extensors (M^0.22), (f) elbow flexors (M^0.22), (g) elbow extensors (M^0.34), (h) supinators (M^0.24), (i) pronators (raw data), (j) wrist flexors (raw data), (k) wrist extensors (raw data), (l) digital flexors (M^0.16), (m) digital extensors (M^0.20). Chimpanzees are shaded in medium grey, bonobos in light grey, gorillas in dark grey and orangutans in white.