Certification Board for Sterile Processing and Distribution (CBSPD) Sterile Processing Technician Practice Exam

Which of the following bones constitutes the upper limbs?

1. Femur

2. Radius

3. Tibia

4. Fibula

The correct answer is: Radius

The correct answer is the radius because it is one of the two long bones located in the forearm of the upper limb, the other being the ulna. The radius is positioned on the lateral side of the forearm in the anatomical position (thumb side) and plays a crucial role in movement and function of the wrist and hand. It articulates with the humerus at the elbow and with the carpal bones at the wrist, making it integral to the mechanics of the upper limb. In contrast, the other bones listed pertain to the lower limb. The femur is the thigh bone, the longest bone in the body, which connects to the hip and knee. The tibia and fibula are the two bones of the lower leg, with the tibia being the larger and more medial of the two, and the fibula positioned laterally. These bones form the skeletal structure that supports weight-bearing activities and movement of the lower extremities.