Which nerves are primarily involved in deep tendon reflexes for the ankle?

The nerves primarily involved in the deep tendon reflexes for the ankle are the S1 and S2 nerve roots. The ankle jerk reflex, or Achilles tendon reflex, is predominantly mediated by the S1 nerve root. This reflex is an important part of assessing the integrity of the sacral segment of the spinal cord and helps evaluate the function of the lower extremities.

When the Achilles tendon is tapped, sensory nerve fibers conduct the signal to the spinal cord at the S1 level, where the motor response is elicited, causing the gastrocnemius and soleus muscles to contract and produce plantar flexion at the ankle. This response confirms that the neural pathways from the spinal cord to the leg muscles are intact, specifically through the S1 segment.

Other choices refer to nerve roots that do not directly correlate with the ankle reflex. For example, the lumbar nerve roots (L2, L3, L4) primarily relate to knee reflexes and hip flexion, while the cervical roots (C5, C6 and C6, C7) are involved in upper extremity functions and reflexes. Therefore, the answer focuses specifically on the S1 nerve roots' role in the reflex arc for the ankle.