Which bone is the larger of the two bones in the lower leg?

The tibia is the larger of the two bones in the lower leg. This bone is also known as the shinbone and is responsible for bearing the majority of the body's weight when standing, walking, or running. The tibia is situated medially (toward the center of the body) in relation to the fibula, which is the thinner bone located on the lateral side (outer side) of the lower leg.

This anatomical arrangement allows the tibia to provide both structural support and a stable surface for muscle attachment, enabling efficient movement and strength in the lower leg. The fibula, while important for providing stability to the ankle and supporting the muscles of the lower leg, does not contribute significantly to weight-bearing. Understanding the differences in size and role between these bones is crucial for EMTs when assessing injuries or conditions involving the lower leg.

The other options listed—radius and ulna—are bones found in the forearm, not the lower leg, which makes them irrelevant to this question. The focus on the tibia as the larger bone emphasizes its primary function in locomotion and support in the lower extremity.