anatomy of the motor component
Last reviewed 01/2018
The motor component of cranial nerve IX begins in the rostral part of the nucleus ambiguus in the reticular formation of the medulla. The nucleus receives input from the cortex.
The glossopharyngeal nerve passes from the nucleus through the jugular foramen to descend with the vagus nerve lateral to the pharyngeal wall. The nerve passes between the superior and middle constrictors to supply the stylopharyngeus muscle and also the superior constrictors.
A dysfunction of innervation in the motor component of the glossopharyngeal nerve results in abnormal control of the palate and pharynx, and hence dysphagia.