Abstract
Angles of hindlimb joints in the extreme flexion and extension caused passively under anaesthesia were examined in 8 male and 8 female Japanese macaques. A hypothetical complete flexion and extension of the joints was regarded as 0° and 180°, respectively. Hip joint angle in maximum extension was 138±7.9° (mean±SD), without a significant sex difference. The anterior thigh touched the belly at a hip joint angle of about 50°. Knee joint angle in maximum extension decreased from 162.9±9.9° to 153.8±10.2°, corresponding to a reduction of the hip joint angle from 125° to 55°, i. e. from an extended position to a flexed one. The heel touched the posterior thigh at a knee joint angle of 30°. While a knee joint flexion allowed a complete plantar flexion and dorsiflexion of the ankle joint, extension of the former seriously limited a dorsiflexion of the latter. Obtained results were briefly discussed in terms of the influence of double-jointed muscles and the joint motion during walking.
