Initially, these bones were identified as a human arm bone (humerus) and the head of a human femur, thought to belong to an individual who lived more than 20,000 years ago. Despite the initial ...

There is one radius (R1) and one ulna (U1); these are the two bones that connect the wrist and elbow. There are two humerus bones (H1 and H2). The humerus connects the shoulder and the elbow.