American Board of Surgery Qualifying Exam (ABS QE) Practice Test

What is the cause of hoarseness following vagus nerve injury?

1. Loss of sensation in the throat

2. Paralysis of the vocal cords

3. Increased secretions in the airway

4. Loss of ability to swallow

The correct answer is: Paralysis of the vocal cords

Hoarseness following vagus nerve injury primarily results from paralysis of the vocal cords. The vagus nerve plays a crucial role in innervating the muscles responsible for controlling the vocal cords, specifically those that facilitate their movement in phonation. When the vagus nerve is injured, it can lead to damage in the recurrent laryngeal nerve, a branch of the vagus that innervates the majority of the intrinsic muscles of the larynx. This paralysis disrupts the normal function of the vocal cords, leading to altered vibrations and sound production, which manifests as hoarseness or voice changes. While other options may relate to the broader implications of vagus nerve damage, they do not directly cause hoarseness. For instance, loss of sensation in the throat may contribute to other issues, but it does not affect the voice itself. Similarly, increased secretions in the airway or loss of swallowing ability may arise from vagal dysfunction but are not directly tied to the changes in voice production. The primary mechanism for vocal alteration specifically linked to vagus nerve injury is indeed the paralysis of the vocal cords.