Which sensory nerve is stimulated to produce laryngospasm?

The internal branch of the superior laryngeal nerve is responsible for providing sensory innervation to the mucosa of the larynx above the vocal cords. When this area is stimulated or irritated, it can lead to a protective reflex known as laryngospasm, which is a sudden involuntary contraction of the muscles of the larynx. This reflex is a protective mechanism to prevent aspiration of foreign materials into the airway. Since the internal branch specifically serves this function by relaying sensory information from above the vocal cords, it is directly involved in the initiation of laryngospasm in response to irritants or other stimuli.

In contrast, the recurrent laryngeal nerve primarily provides motor innervation to most of the intrinsic muscles of the larynx and carries sensory fibers from the larynx below the vocal cords but does not play a direct role in laryngospasm. The trigeminal nerve, while important in facial sensation, does not primarily impact laryngeal reflexes and does not innervate the laryngeal structures in a way that would lead to laryngospasm. The vagus nerve is broader in its function, controlling many autonomic functions, but it does not provide the specific sensory innervation