What nerve root is tested by tibialis anterior?

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Multiple Choice

What nerve root is tested by tibialis anterior?

Explanation:
Tibialis anterior strength mainly reflects the L4 myotome. This muscle is innervated by the deep peroneal nerve, which carries fibers from the L4 and L5 roots, but dorsiflexion of the foot (lifting the foot toward the shin) is classically mapped to L4. In a neuro exam, asking the patient to dorsiflex against resistance tests this L4 function; weakness here points to an L4 involvement (radiculopathy or peroneal nerve issue). By contrast, weakness in great toe extension points toward L5, and plantarflexion weakness points toward S1. If dorsiflexion is preserved while other movements fail, that helps localize the deficit more precisely.

Tibialis anterior strength mainly reflects the L4 myotome. This muscle is innervated by the deep peroneal nerve, which carries fibers from the L4 and L5 roots, but dorsiflexion of the foot (lifting the foot toward the shin) is classically mapped to L4. In a neuro exam, asking the patient to dorsiflex against resistance tests this L4 function; weakness here points to an L4 involvement (radiculopathy or peroneal nerve issue). By contrast, weakness in great toe extension points toward L5, and plantarflexion weakness points toward S1. If dorsiflexion is preserved while other movements fail, that helps localize the deficit more precisely.

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