## **Core Concept**
The hypoglossal nerve (cranial nerve XII) is responsible for controlling the muscles of the tongue. Injury to this nerve can lead to difficulties in tongue movement, affecting speech and swallowing. The primary muscle it innervates is the genioglossus, which is crucial for protruding the tongue.

## **Why the Correct Answer is Right**
The correct answer, , is associated with the clinical presentation of hypoglossal nerve injury. When the hypoglossal nerve is damaged, the affected individual may experience weakness or paralysis of the tongue muscles on the same side as the injury. This leads to difficulty in protruding the tongue, and when attempting to do so, the tongue deviates towards the side of the lesion due to the unopposed action of the intact genioglossus muscle on the contralateral side.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option is incorrect because it does not accurately describe a consequence of hypoglossal nerve injury.
- **Option B:** This option is incorrect as it does not relate to the function or consequence of hypoglossal nerve damage.
- **Option C:** This option is incorrect because it is actually the correct answer but let's evaluate the rest.

## **Clinical Pearl / High-Yield Fact**
A key clinical test for assessing hypoglossal nerve function is asking the patient to protrude their tongue. If there is a lesion of the hypoglossal nerve, the tongue will deviate to the side of the lesion upon protrusion. This is a quick and effective bedside test for identifying hypoglossal nerve injury.

## **Correct Answer:** . Deviation of tongue to the side of lesion.