nucleus ambiguus

A region of histologically disparate cells located just dorsal to the inferior olivary nucleus in the lateral portion of the upper medulla. It receives upper motor neuron innervation directly via the corticobulbar tract This nucleus gives rise to the efferent motor fibers of the vagus nerve terminating in the laryngeal and pharyngeal muscles, as well as to the efferent motor fibers of the glossopharyngeal nerve (CN IX) terminating in the stylopharyngeus. [WP,unvetted].