Overall, the forearm comprises half of the arm. It extends from the elbow joint to the hand, and it is made up of the ulna and radius bones. These two long bones form a rotational joint, as the forearm can roll into pronated and supinated positions. Also, the forearm is covered by skin, which provides a sensory function. Predominance of hair on the forearm varies on different people, but typically the top features more follicles than the underside. Two large arteries run the distance of the forearm, and these are the radial and ulnar. Both blood vessels follow a course close to the bones of similar name. These vessels also branch and lesser arteries, servicing the forearm's musculature. Many of the forearm's components are innervated by the radial, ulnar, and median nerves, as well as their subsequent branches. On the whole, the entire arm features three long bones that are frequently broken. This is especially true for the forearm. Often, a person extends their forearm instinctually when trying to break a fall.
Written and medically reviewed by the Healthline Editorial Team
In Depth: Forearm