A patient underwent lateral skull base surgery few months back and has presented with complaints of recurrent aspirations. There is no change in voice of the patient. Which of the following nerve is most likely injured during surgery?
**Core Concept**
The patient's symptoms of recurrent aspirations with no change in voice suggest a problem with swallowing, specifically the coordination between the muscles involved in the process. This points to an issue with the cranial nerves controlling these muscles.
**Why the Correct Answer is Right**
The recurrent laryngeal nerve (RLN) is responsible for innervating the intrinsic muscles of the larynx, which control voice production. However, the RLN also has a branch that supplies the cricothyroid muscle, which is involved in pitch and tension of the vocal cords. The vagus nerve (cranial nerve X) gives off the RLN, and the RLN runs a long course around the subclavian artery (on the right side) or the aortic arch (on the left side) before returning to the larynx. Given the patient's symptoms of recurrent aspirations, it is likely that the RLN has been injured, affecting the function of the laryngeal muscles involved in swallowing, but spares the muscles responsible for voice production.
**Why Each Wrong Option is Incorrect**
**Option A:** The glossopharyngeal nerve (cranial nerve IX) is involved in swallowing and taste, but it is not primarily responsible for the symptoms described. It supplies the stylopharyngeus muscle, which is not directly related to the patient's symptoms.
**Option B:** The vagus nerve (cranial nerve X) is the parent nerve of the RLN, but the question is asking about the specific nerve most likely injured, not the nerve from which it originates.
**Option C:** The accessory nerve (cranial nerve XI) supplies the sternocleidomastoid and trapezius muscles, which are not directly involved in the patient's symptoms of recurrent aspirations.
**Clinical Pearl / High-Yield Fact**
The RLN has a long and tortuous course around the subclavian artery or aortic arch, making it vulnerable to injury during neck and thoracic surgery. Remembering this anatomy is crucial in avoiding nerve damage during surgical procedures.
**Correct Answer:** C. Recurrent laryngeal nerve.