13/08/2022
These two nerves are mixed motor, sensory, and parasympathetic; the glossopharyngeal nerve is mainly sensory, the vagus nerve is mainly motor, their nuclei are in the medulla oblongata.
They are examined in 5 steps:
1. Search for dysarthria and dysphonia: by taking history from the patient, listen for nasal dysarthria, spastic dysarthria, dysphonia
(hoarseness of voice).
2. Testing swallowing by giving the patient a glass (cup) of water and asking the patient to drink it in one piece, look for swallowing difficulty, nasal regurgitation, choking, cough.
Note: dysarthria and swallowing difficulty usually occur in bilateral glossopharyngeal and vagus nerve lesions, sometimes seen transiently in acute unilateral lesions.
3. Movement of the uvula on saying “Ah”: normally the uvula elevates centrally, if there is weakness of the vagus nerve the uvula deviates to the normal side.
4. Gag reflex: touching the posterior pharyngeal wall (medial to the tonsils) with a tongue depressor leads to gag, repeat the gag reflex on the right and on the left sides. The sensory limb of
gag reflex is the glossopharyngeal nerve, the motor limb is the vagus nerve, and the center is in the medulla oblongata.
5. Sensation in the posterior pharyngeal wall.
