Which movement is primarily controlled by the L4 myotome?

Which movement is primarily controlled by the L4 myotome?

• A. Great toe extension
• B. Ankle dorsiflexion
• C. Knee flexion
• D. Ankle eversion

Answer: (B)

Ankle dorsiflexion is the movement controlled by the L4 myotome. This action is performed primarily by the tibialis anterior, which is innervated mainly by the L4 nerve root via the deep peroneal nerve. Great toe extension is mainly associated with the L5 myotome (extensor hallucis longus), knee flexion involves hamstring muscles predominantly supplied by L5–S1, and ankle eversion relies more on muscles innervated by L5–S1. Therefore, dorsiflexion best reflects L4 function.

Ankle dorsiflexion is the movement controlled by the L4 myotome. This action is performed primarily by the tibialis anterior, which is innervated mainly by the L4 nerve root via the deep peroneal nerve.

Great toe extension is mainly associated with the L5 myotome (extensor hallucis longus), knee flexion involves hamstring muscles predominantly supplied by L5–S1, and ankle eversion relies more on muscles innervated by L5–S1. Therefore, dorsiflexion best reflects L4 function.