The glossopharyngeal nerve (cranial nerve IX) leaves the side of the upper medulla oblongata, between the olive and the inferior cerebellar peduncle, just in front of the vagus nerve. It leaves the skull through the central part of the jugular foramen, together with the vagus (X) and accessory (XI) nerves, and runs down past the styloid process to the back of the tongue and the throat. [1]
The 3D brain needs JavaScript. The text below still says where the glossopharyngeal nerve is and what it does.
Opens cut by a side (sagittal) slice through the medulla oblongata, which the glossopharyngeal nerve leaves the brain from. Drag to turn, pinch or scroll to zoom, tap any part to name it; .
Not a separate shape in this atlas; lit: the part it leaves the brain from. Lit: the whole medulla oblongata, the part the glossopharyngeal nerve leaves the brain from. The nerve itself, which runs on to the tongue and throat, has no shape in the BodyParts3D model, so nothing is drawn for it at a guessed point. [2][1]
Where it leaves the brain: the medulla oblongata. Its rootlets come out of the side of the upper medulla, between the olive and the inferior cerebellar peduncle, at the top of the row the vagus (X) rootlets continue below it. [1][3]
Lit here: the medulla oblongata, the part the glossopharyngeal nerve leaves the brain from — see it on its own page.
Next to it, each lit on its own page: vagus nerve.
Where it is
Its fibres start or end in four nuclei of the medulla: the solitary nucleus (taste and the carotid signals), the spinal nucleus of the trigeminal nerve (touch, pain and temperature), the nucleus ambiguus (its one muscle) and the inferior salivatory nucleus (the parotid gland). [1]
It leaves the skull through the central part of the jugular foramen, with the vagus (X) and accessory (XI) nerves; in the foramen it lies in front of and to the side of those two, and two swellings on it there, the superior and inferior glossopharyngeal ganglia, hold the cell bodies of its sensory fibres. [1][4]
Below the skull it passes between the internal jugular vein and the internal carotid artery, runs down beneath the styloid process to the stylopharyngeus muscle, arches forward across the side of the throat and ends under the hyoglossus muscle in the tonsil, the back of the tongue and the glands of the mouth. [1]
What it does
Taste from the back third of the tongue, including the large circumvallate papillae, and touch, pain and temperature from the back third of the tongue, the upper throat (pharynx), the tonsils and the inner surface of the eardrum. [1][5]
Its only muscle is the stylopharyngeus, which lifts the throat during swallowing and speech. [1]
Its parasympathetic fibres drive the parotid salivary gland, by way of the lesser petrosal nerve and the otic ganglion. [1][5]
It carries signals on blood pressure from the carotid sinus and on blood oxygen and carbon dioxide from the carotid body, which reach the solitary nucleus and feed the reflexes that adjust heart rate and breathing. Touching the back of the throat sends the incoming half of the gag reflex along this nerve; the outgoing half runs in the vagus. [1]
Connections
Its branches: the tympanic nerve (to the middle ear), the stylopharyngeal nerve, tonsillar branches, the carotid sinus nerve, lingual branches to the back third of the tongue, and a branch joining the vagus. With the vagus it forms the pharyngeal plexus on the wall of the throat. [1]
Taste signals it brings to the solitary nucleus go on to the thalamus (its ventral posteromedial nucleus) and from there to the taste area of the cortex in the parietal lobe. [1]
Other names
Cranial nerve IX (CN IX), ninth cranial nerve. The name joins the Greek for tongue (glossa) and throat (pharynx), the two places it supplies. [1]
Size
The model has no shape for the glossopharyngeal nerve, so it is not measured here. The medulla oblongata, lit as the part it leaves the brain from, measures about 33 mm front to back, 41 mm top to bottom and 27 mm side to side on this model (the box it fits in, not its volume). [2]
Facts describe anatomy and normal function only. The 3D model is the adult male BodyParts3D brain (credits and licence); real brains vary in size and shape, so its measurements describe one model, not anyone’s brain.