Structural Strength of the Femur of Bipedally Trained Monkey

Structural strength of the femur of a Japanese monkey which had been trained for bipedalism for 11 years was studied using CT images. Cross-sectional properties were obtained at below the lesser trochanter level and at mid-length level. The analysis revealed significantly greater strength of the bone compared to ordinary monkeys. Despite greatly increased structural strength, bending rigidity pattern of the diaphysis is similar to that of ordinary monkeys rather than humans. Modifications are more apparent at below the lesser trochanter level than at the mid-length level. This may suggest that the muscle activities, which stabilize the hip joint, severely affect the proximal femur shaft in monkey bipedalism.