Which muscle is associated with the L4 motor nerve root during examination?

The tibialis anterior muscle is primarily innervated by the L4 motor nerve root, making it the correct choice in this scenario. The tibialis anterior is responsible for dorsiflexion of the foot and plays a crucial role in controlling foot movement during walking and running.

During a neurological examination, assessing the function of the L4 nerve root often involves evaluating the strength of the tibialis anterior. Weakness in dorsiflexion can indicate an issue with the nerve root that corresponds to the L4 level in the spinal cord. This muscle is also involved in ankle inversion, which is another key action tested during the assessment.

In contrast, the quadriceps, while also involved in movements affected by the L4 root, is primarily associated with the L3 nerve root for knee extension. The gastrocnemius is innervated mainly by the S1 nerve root and is involved in plantarflexion and flexion of the knee. The extensor hallucis longus is primarily associated with the L5 nerve root, as it aids in the extension of the big toe and helps with dorsiflexion of the foot but is not as directly linked to L4 motor function.

Thus, identifying the tibialis anterior as the muscle linked to