The pharyngeal constrictor muscles are primarily innervated by which nerve?

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Swallowing action in the pharynx relies on the motor input to the pharyngeal constrictor muscles, which comes through the vagus nerve via the pharyngeal plexus. The vagus supplies most muscles of the pharynx (and the larynx) after wiring into this plexus, driving the sequential constriction that pushes a bolus downward. The glossopharyngeal nerve mainly supplies the stylopharyngeus muscle, not the constrictors, so it doesn’t provide the primary innervation here. The trigeminal nerve handles muscles from the first pharyngeal arch (like tensor veli palatini) but not the pharyngeal constrictors. The facial nerve serves muscles of facial expression and other structures, not the pharyngeal constrictors. Thus, the nerve most responsible for innervating the pharyngeal constrictor muscles is the vagus nerve.