Figure 4.

Lateral-to-medial views of the right forelimb and hind-limb skeletons of an adult horse showing a spectrum from simple loading to complex loading, respectively: calcaneus (A), radius (B), and third metacarpal (MC3) (C). The drawings below are simplified renditions of each bone type, showing: A) the calcaneus as a cantilevered beam, B) the radius as a curved beam with longitudinal loading; the curvature accentuates bending. Torsion (dotted line) is also present but is less than the torsion in the MC3 (solid circular line in C), and C) the MC3 with off-axis longitudinal loading producing bending and torsion, the latter being greater than in the other two bones. Several studies reporting in vivo strain data were used to create these drawings (Lanyon, 1974; Turner et al., 1975; Rubin and Lanyon, 1982; Schneider et al., 1982; Biewener et al., 1983a; Biewener et al., 1983b; Gross et al., 1992; Su et al., 1999).