What cranial nerve provides the motor supply to the pharynx?

The vagus nerve (CN X) is the cranial nerve that provides motor supply to the pharynx. It plays a crucial role in swallowing by innervating the majority of the pharyngeal muscles, which are essential for the coordination and propulsion of food from the mouth to the esophagus. The vagus nerve also innervates muscles of the soft palate, further assisting in swallowing and preventing food from entering the nasal cavity.

In contrast, the trigeminal nerve (CN V) primarily provides sensory innervation to the face and motor supply to the muscles of mastication, not the pharyngeal muscles. The facial nerve (CN VII) is largely associated with facial expressions and the motor supply to the muscles of the face, as well as taste sensation from the anterior two-thirds of the tongue. The hypoglossal nerve (CN XII) is responsible for controlling the movements of the tongue, which is important for speech and swallowing but does not innervate the pharyngeal muscles. Therefore, the vagus nerve is correctly identified as the one that supplies motor function to the pharynx.