L2 myotome is tested by which movement?

L2 myotome is tested by which movement?

• A. Ankle dorsiflexion
• B. Hip flexion
• C. Knee extension
• D. Great toe extension and hip abduction

Answer: (B)

Hip flexion is used to test the L2 myotome because the iliopsoas, the primary hip flexor, is mainly innervated by the L2 nerve root. When you have the patient lie supine and test lifting the thigh toward the chest (hip flexion) while applying resistance to the thigh, you’re evaluating the strength of this muscle group and thus the integrity of the L2 nerve root. If L2 is compromised, hip flexion weakens, signaling involvement at this level. The other movements align with different nerve roots: ankle dorsiflexion involves the tibialis anterior (often L4–L5), knee extension involves the quadriceps (L3–L4), and great toe extension involves the extensor hallucis longus (L5). Hip abduction mainly tests gluteal muscles (different roots, typically L4–S1), not L2.

Hip flexion is used to test the L2 myotome because the iliopsoas, the primary hip flexor, is mainly innervated by the L2 nerve root. When you have the patient lie supine and test lifting the thigh toward the chest (hip flexion) while applying resistance to the thigh, you’re evaluating the strength of this muscle group and thus the integrity of the L2 nerve root. If L2 is compromised, hip flexion weakens, signaling involvement at this level.

The other movements align with different nerve roots: ankle dorsiflexion involves the tibialis anterior (often L4–L5), knee extension involves the quadriceps (L3–L4), and great toe extension involves the extensor hallucis longus (L5). Hip abduction mainly tests gluteal muscles (different roots, typically L4–S1), not L2.