## **Core Concept**
The H-reflex, also known as the Hoffmann reflex, is an electrophysiological test used to assess the integrity of the peripheral nervous system, particularly the afferent and efferent pathways of the reflex arc. It is commonly used to evaluate S1 nerve root function and the peripheral nerves.

## **Why the Correct Answer is Right**
The H-reflex is specifically associated with the **Soleus muscle**. When the **tibial nerve** is stimulated, it activates the afferent (sensory) fibers, which then stimulate the efferent (motor) fibers to the soleus muscle, causing a reflex contraction. This reflex is a measure of the **monosynaptic reflex arc**, which includes the afferent neuron, one synapse in the spinal cord, and the efferent neuron. The H-reflex is particularly useful in diagnosing conditions affecting the peripheral nerves and nerve roots.

## **Why Each Wrong Option is Incorrect**
- **Option A:** While **Median nerve** stimulation can elicit various reflexes, the H-reflex is not typically associated with it. The median nerve primarily supplies muscles of the forearm and hand.
- **Option B:** The **Tibial nerve** is indeed involved in the H-reflex, but the reflex itself is specifically related to the muscle it activates, which is not listed here but implied through the association with **Soleus**.
- **Option C:** **Triceps Surae** is a muscle group that includes the soleus and gastrocnemius muscles. While related, the H-reflex specifically refers to the reflex in the **Soleus muscle**, not the muscle group as a whole.

## **Clinical Pearl / High-Yield Fact**
The H-reflex of the **Soleus muscle** is particularly useful in clinical settings for assessing **S1 nerve root** function. A delayed or absent H-reflex can indicate nerve root compression or peripheral neuropathy affecting the S1 root or the tibial nerve.

## **Correct Answer:** B. Soleus.