What is the four-sided bone of the forearm that is on the same side as the thumb?

The four-sided bone of the forearm that is located on the same side as the thumb is the radius. This bone is one of the two long bones in the forearm, the other being the ulna. The radius is positioned laterally in the standard anatomical position, which means when a person stands with their arms at their sides and palms facing forward, the radius is on the thumb side of the forearm. This characteristic is essential for both understanding human anatomy and for practical applications in fields like medicine and physical therapy.

The ulna, in contrast, is found on the opposite side of the forearm, aligning with the pinky finger. The fibula and tibia are actually bones of the leg, not the forearm, which helps clarify why they are not relevant answers in this case.