Life Span and Anatomy & Physiology Practice Test 2026 - Free Practice Questions and Study Guide

In the forearm, there are two long bones: the radius and the ulna. In the usual anatomical position, the radius sits on the thumb side, while the ulna is on the opposite side, toward the little finger. This makes the ulna the bone on the side opposite the thumb. The other options aren’t forearm bones: carpals are wrist bones, and vertebrae are in the spine. So the bone on the pinky-side of the forearm is the ulna.