Which bone is the forearm bone on the thumb side?

Which bone is the forearm bone on the thumb side?

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

Answer: (C)

Understanding forearm anatomy and the standard position helps identify which bone is on the thumb side. The forearm has two long bones: the radius and the ulna. In the usual anatomical position (standing with arms at the sides and palms facing forward), the radius sits on the thumb side. It extends from the elbow to the wrist and crosses over the ulna when you rotate the forearm, allowing movements called pronation and supination. The ulna lies on the pinky side. The carpals are the wrist bones, not forearm bones, and the humerus is the upper arm bone. So, the bone on the thumb side is the radius.

Understanding forearm anatomy and the standard position helps identify which bone is on the thumb side. The forearm has two long bones: the radius and the ulna. In the usual anatomical position (standing with arms at the sides and palms facing forward), the radius sits on the thumb side. It extends from the elbow to the wrist and crosses over the ulna when you rotate the forearm, allowing movements called pronation and supination. The ulna lies on the pinky side. The carpals are the wrist bones, not forearm bones, and the humerus is the upper arm bone. So, the bone on the thumb side is the radius.