International Sports Sciences Association (ISSA) Trainer Practice Exam

What two bones form the wrist joint with the carpal bones?

1. Radius and femur

2. Radius and ulna

3. Radius and tibia

4. Ulna and fibula

The correct answer is: Radius and ulna

The wrist joint is formed by the interaction between the carpal bones and two specific bones in the forearm: the radius and the ulna. The radius, which is located on the thumb side of the forearm, plays a pivotal role in forming the wrist joint, as it directly articulates with the carpal bones. The ulna is located on the side opposite the radius (the pinky side) and, while it does not directly articulate with the carpal bones, it aids in the stability and overall function of the wrist joint through its connection to the carpal structures via ligaments. Together, these two bones (radius and ulna) create the proper anatomical foundation needed for the wrist's complex movements, including flexion, extension, and radial and ulnar deviation. The other options, which suggest the inclusion of the femur, tibia, or fibula, are incorrect as they pertain to the leg rather than the arm. The femur is the thigh bone, the tibia is the larger bone in the lower leg, and the fibula is the smaller bone located alongside the tibia in the lower leg. None of these bones are involved in forming the wrist joint with the carpal bones.