Which reflex is used to assess L4 nerve root pathology?

The patellar reflex is utilized to assess L4 nerve root pathology. This reflex is also known as the knee-jerk reflex. When the patellar tendon is tapped, it sends a signal through the L4 nerve root to the spinal cord and back, causing the quadriceps muscle to contract, resulting in a kick of the lower leg.

Evaluating this reflex is crucial when assessing for potential issues relating to the L4 nerve root, as damage or dysfunction in this area may lead to diminished or absent reflexes. It serves as a primary indicator of the integrity of the L4 nerve root and more broadly contributes to the neurological examination of the lower extremities.

Other reflexes, such as the plantar reflex, Achilles reflex, and biceps reflex, serve to assess different nerve roots and pathways, but they do not specifically evaluate the L4 nerve root. The plantar reflex primarily assesses the S1-S2 nerve roots, the Achilles reflex assesses the S1 nerve root, and the biceps reflex evaluates the C5-C6 nerve roots. Therefore, the patellar reflex is the precise choice for determining L4 nerve root pathology.