Primate arms have one long bone, the humerus, in the upper arm above the elbow, and two thinner bones, the radius and ulna, in the forearm.
灵长类的上臂有一根长骨(肱骨),前臂有两根细骨(尺骨和桡骨)。
3
Location: two and one-half finger widths above the center of the wrist crease on the outside of the forearm midway between the two bones (ulna and radius).