What cranial nerve is responsible for sensory input from the external acoustic meatus?

The correct answer is the vagus nerve (Cranial Nerve X), which is indeed responsible for sensory input from the external acoustic meatus. The vagus nerve has multiple functions and a broad distribution throughout the body, including innervation to areas of the throat, larynx, and various visceral organs.

In the context of the external acoustic meatus, the vagus nerve provides sensory input that pertains to the pathways for sensations such as touch, pain, and temperature from this area. This sensory information is critical, as it not only contributes to our ability to perceive sensations from the ear canal but also plays a part in protective reflexes, such as the cough reflex, which is triggered by stimuli in the area.

The oculomotor nerve (Cranial Nerve III) primarily controls eye movements and the pupillary response, making it unrelated to sensory input from the external acoustic meatus. The trigeminal nerve (Cranial Nerve V), while it does provide sensation to the face, is more involved with sensory functions of the facial area rather than the auditory canal. The facial nerve (Cranial Nerve VII) primarily innervates muscles of facial expression and conducts taste sensations but does not carry sensory information