From radiographic data on the second metacarpal of three different populations (Ohio, Guatemala, El Salvador) the endosteal and periosteal radii were determined. From these values the cross sectional area was calculated and the specific growth rate, a “vibration frequency” and the ratio of the outer radius to the inner radius were determined. The three populations showed qualitative similarities in the calculated parameters. The cross sectional bone area of the males and females in any one population closely followed each other until about age 11; the values in females leveled off while those in males continued to increase and plateaued at a higher value. The specific growth rate in both sexes showed a decrease with age until puberty, when a leveling off or actual increase occurred; this was followed by a second decrease in the specific growth rate. The “vibration frequency” showed a complex behavior up to approximately age 20 in males. It then leveled off in the males until a second decrease occurred beginning at age 40. In females the “vibration frequency” showed a marked decrease with age after age 40. The ratio of the periosteal radius to the endosteal radius increased until approximately age 40 and then showed an almost linear decrease with age (and resembled the femur).