Which spinal level corresponds to great toe extension?

Which spinal level corresponds to great toe extension?

• A. L4
• B. L5
• C. S1
• D. S2

Answer: (B)

Great toe extension is controlled by the extensor hallucis longus, which dorsiflexes the big toe. The motor fibers for this action come from the L5 nerve root via the deep peroneal nerve. So testing the ability to extend the big toe mainly assesses L5 function. If L5 is impaired, you’ll see weakness in toe extension (and often in related dorsiflexion movements), whereas ankle plantarflexion is more related to S1-S2, and actions like knee extension align with L3-L4. Therefore, L5 is the spinal level associated with great toe extension.

Great toe extension is controlled by the extensor hallucis longus, which dorsiflexes the big toe. The motor fibers for this action come from the L5 nerve root via the deep peroneal nerve. So testing the ability to extend the big toe mainly assesses L5 function. If L5 is impaired, you’ll see weakness in toe extension (and often in related dorsiflexion movements), whereas ankle plantarflexion is more related to S1-S2, and actions like knee extension align with L3-L4. Therefore, L5 is the spinal level associated with great toe extension.