In an L2 radiculopathy with motor weakness, which ipsilateral gait abnormality is MOST likely?

• A. Pelvic drop during swing phase of gait
• B. Hip external rotation during swing phase of gait
• C. Genu valgum during stance phase of gait
• D. Posterior trunk bending in the stance phase of gait

Answer: (B)

When L2 is affected, the hip flexors (primarily the iliopsoas) are weakened. During walking, if hip flexion is limited, the leg may be advanced with a compensatory external rotation of the hip during the swing phase to help clear the foot and allow the thigh to move forward using other muscles. That pattern—hip external rotation in swing on the same side as the weakness—is the most likely ipsilateral gait change with this level of radiculopathy. Pelvic drop would suggest weakness of the stance-leg abductors, which involve higher roots, not mainly L2. Genu valgum and posterior trunk bending describe different compensations not specifically tied to L2 hip flexor weakness. So the external rotation during swing best fits the expected adaptation to reduced hip flexion strength.