To assess spinal function at the S1 level, which deep tendon reflex should be tested?

To assess spinal function at the S1 level, testing the Achilles deep tendon reflex is appropriate because this reflex is primarily mediated by the S1 nerve root. The Achilles reflex, also known as the ankle reflex, involves the contraction of the gastrocnemius and soleus muscles when the Achilles tendon is tapped. This response serves as a vital indicator of the integrity of the S1 nerve root and has specific relevance in evaluating lower limb neurological function.

While other reflexes like the patellar reflex (associated with L2-L4), the cremasteric reflex (associated with L1-L2), and the anal wink reflex (associated with the S2-S4 region) are important for assessing different parts of the neurological system, they do not specifically target the S1 nerve root. Therefore, the Achilles reflex is the most direct means of assessing spinal function at that particular level.