What vocal quality is most likely to be affected by a superior laryngeal nerve injury?

The choice of reduced pitch range as the answer relates to the function of the superior laryngeal nerve, which primarily innervates the cricothyroid muscle. This muscle is crucial for adjusting tension in the vocal cords, which enables a person to vary pitch effectively. When there is an injury to the superior laryngeal nerve, the cricothyroid muscle may not function properly, leading to a diminished ability to manipulate pitch. Consequently, the individual may experience a noticeable limitation in their vocal range, specifically in their ability to sing or speak at higher or lower pitches.

In contrast, inspiratory stridor and hypernasal resonance are more associated with airway obstruction or inadequate closure of the velopharyngeal port, respectively, and complete aphonia would suggest total loss of voice, which usually involves more extensive vocal cord issues rather than isolated issues tied to the superior laryngeal nerve specifically. Thus, when considering the direct effects of a superior laryngeal nerve injury, reduced pitch range is the most accurate result.