Why is the patellar reflex important during a lower extremity assessment?

• A. It tests overall muscle strength.
• B. It assesses the integrity of the L2-L4 spinal segments.
• C. It evaluates coordination between the upper and lower body.
• D. It measures balance and stability.

Answer: (B)

The patellar reflex, also known as the knee-jerk reflex, is significant during a lower extremity assessment because it specifically assesses the integrity of the L2-L4 spinal segments. This reflex is a monosynaptic response that involves the quadriceps muscle and the femoral nerve, which arises from the spinal nerves in the lumbar region, particularly L2, L3, and L4. When the patellar tendon is tapped, it stretches the quadriceps muscle, and a reflex arc is triggered that results in the extension of the knee.

By evaluating this reflex, clinicians can gather important information about the neurological function and potential impingements or lesions along the lumbar spine. A normal patellar reflex suggests that the neurological pathway is intact, while an absent or diminished reflex may indicate issues within the associated spinal segments.

While overall muscle strength, coordination between the upper and lower body, and balance are important aspects of a physical assessment, they are not specifically tested by this reflex. The patellar reflex is focused on a specific neurological function rather than broader assessments of strength or stability.