Which motor level function would likely require less reliance on upper extremities and may use an AFO?

• A. L3
• B. L2
• C. L5
• D. L4

Answer: (D)

The main idea is that independent walking with an ankle–foot orthosis hinges on having enough control at the knee and hip, while the ankle requires support to stay properly aligned. An AFO helps keep the ankle in a stable position and assists with foot clearance during swing, so the person can ambulate with less need to push with the arms for balance. The L4 motor level corresponds to the ability to control ankle dorsiflexion (with the tibialis anterior) enough to make gait feasible when the ankle is stabilized by an orthosis. With preserved proximal strength at the hip and knee, this allows standing and stepping with reduced reliance on the upper extremities. In contrast, more proximal weaknesses (L2/L3) increase the need for arm support, while L5 involves different distal functions that don’t address ankle control as directly for the typical use of an AFO.