Which bone is the outer bone of the forearm, on the side of the thumb?

Which bone is the outer bone of the forearm, on the side of the thumb?

• A. Radius
• B. Ulna
• C. Humerus
• D. Clavicle

Answer: (A)

In anatomical position, the forearm has two bones: the radius and the ulna. The radius sits on the outside of the forearm on the thumb side, so it’s the outer bone described. The ulna runs along the pinky side. The humerus is the upper arm bone, and the clavicle is the collarbone, so they don’t fit the description.

In anatomical position, the forearm has two bones: the radius and the ulna. The radius sits on the outside of the forearm on the thumb side, so it’s the outer bone described. The ulna runs along the pinky side. The humerus is the upper arm bone, and the clavicle is the collarbone, so they don’t fit the description.