the radius – connects the elbow to the wrist on the thumb side of the hand

(Pronounced ray-dee-us)

To remember the meaning of the radius, remember that it connects to the thumb side of the wrist, and use the following mnemonic:

You cannot change stations on the wrist radios (radius) without using your thumb (thumb side).

The radius is one of the two long bones in the forearm, running parallel to the ulna from the elbow to the wrist on the thumb side of the wrist. At the elbow joint, the radius has a smaller role compared to the ulna, with its rounded upper end articulating with both the humerus and the ulna, allowing it to rotate freely during movements that allow the hand to turn palm up or palm down. 

The radius is the smaller of the two forearm bones at the elbow, but becomes the larger and more prominent bone at the wrist, where it forms the primary connection with the wrist bones and plays the dominant role in wrist movement and hand positioning. 

This bone is essential for the proper functioning of the hand and wrist, as it transmits force from the hand to the rest of the arm and provides the structural framework that supports the thumb side of the hand during gripping and manipulation activities.