An experimental model using immature bovine femora and tibiae was used to determine the varying patterns of failure in and around the physis when the direction of stress was varied. Compression, tension, shear, and torque were individually applied. The results showed that the histologic failure pattern did vary with each type of applied load. Compression resulted in failure in the zone of provisional calcification and the metaphysis rather than the previously hypothesized germinal zone. Tension loads caused failure in the upper zone of columnation. Failure in between the upper zone of columnation and lower zone of hypertrophy was caused by shear loads. Torque resulted in failure through all zones.