FIGURE 1. Terminology of muscle anatomy as used in this study. 1 – 5) Different degrees of evolutionary differentiation (for details see text). Left = anterior. A – F) Different muscle shapes and fibre courses. A) parallel fibred with two direct attachments, B) parallel fibred with one tendinous attachment, C) fan shaped, D) spindle shaped, E) bipinnated muscle including two portions, F) pinnated, G) bipinnated muscle not separated into two portions.