Which of the following is not seen in unilateral injury to hypoglossal nerve
**Core Concept**
Unilateral injury to the hypoglossal nerve (CN XII) can lead to various clinical manifestations due to its role in controlling the motor function of the tongue. The hypoglossal nerve is responsible for innervating the muscles of the tongue, except for the palatoglossus, which is innervated by the vagus nerve (CN X).
**Why the Correct Answer is Right**
In a unilateral injury to the hypoglossal nerve, the affected side of the tongue will deviate towards the side of the lesion on protrusion due to the unopposed action of the muscles on the unaffected side. This is because the hypoglossal nerve supplies all the extrinsic and intrinsic muscles of the tongue, except for the palatoglossus. The deviation is a result of the imbalance in muscle forces, with the muscles on the unaffected side pulling the tongue away from the midline.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not relevant to the clinical manifestations of unilateral hypoglossal nerve injury.
* **Option B:** Atrophy of the tongue muscles is a possible outcome of long-standing hypoglossal nerve damage, but it is not a specific consequence of unilateral injury.
* **Option D:** This option is a potential complication of hypoglossal nerve injury, but it is not a direct result of unilateral injury.
**Clinical Pearl / High-Yield Fact**
It's essential to remember that the hypoglossal nerve does not have any motor branches to the muscles of the face, and its injury will not result in facial weakness or paralysis.
**Correct Answer:** None of the above