Modelling the muscles of the scapula morphometric and coordinate data and functional implications

Modelling of the shoulder mechanism is dependent upon reliable data on the morphometry and points of attachment of the relevant muscles. In this paper, the authors present coordinate data which have been derived from the radiography of dissected cadavers. All of the coordinates have been normalised with respect to reference dimensions of the relevant segments (humerus, scapula, clavicle and trunk). Similarly the measurements of physiological cross-section area (PCSA) have been normalised with respect to that of deltoid. The measurements of PCSA have been shown to agree largely with the work of Veeger et al. [J. Biomechanics 24, 615-629 (1991)] and Karlsson and Peterson [J. Biomechanics 25, 189-199 (1992)]. While the majority of the descriptions of morphometry concur with accepted texts there are some notable disagreements, particularly concerning trapezius.