Glossopharyngeal IX ,Vagus X and Accessory XI nerves D.Nimer D.Rania Gabr D.Safaa D.Elsherbiny

Glossopharyngeal (1X) Cranial nerve Type: mixed nerve. It contains motor, parasympathetic and sensory fibers. Fiber Contents and their Origin: 1. Motor fibers: from the upper part of the nucleus ambiguus in the medulla to the stylopharyngeus muscle. 2. Parasympathetic secretomotor fibers: from the inferior salivatory nucleus in the medulla to the parotid gland. 3. Sensory fibers: have their origin in the 2 ganglia of the glossopharyngeal nerve (superior and inferior; jugular and petrosal) a. Taste fibers from the posterior 1/3 of the tongue to the upper 1/3 of the nucleus solitarius. b. General sensory fibers from the posterior 1/3 of the tongue, tonsil, middle ear & pharynx to the lower 2/3 of nucleus solitarius.

Exit from the Brain: in the postolivary fissure Exit from the Skull: through the jugular foramen. Course: passes in the upper part of the carotid sheath between the internal carotid artery and the internal jugular vein → passes between the internal and external carotid arteries → passes between the middle and superior constrictors.

Branches and Distribution: 1. Tympanic branch: forms the tympanic plexus, which supplies the middle ear, mastoid antrum and auditory tube. From the plexus arises the lesser petrosal nerve, which carries preganglionic parasympathetic fibers to the otic ganglion and the parotid gland. 2. Motor branch: to the stylopharyngeus muscle. 3. Carotid sinus nerve: supplies sensory fibers to the carotid sinus (pressoreceptor) for the regulation of blood pressure. 4. Communicating branch: with the auricular branch of the vagus (carries sensory fibers from behind the ear).

5. Three terminal branches: pharyngeal, tonsillar and lingual Pharyngeal branch: forms the sensory root of the pharyngeal plexus and supplies the pharyngeal mucosa. b. Tonsillar branch: sensory to the palatine tonsil and soft palate. c. Lingual branch: general sensory and taste fibers to the posterior one-third of the tongue and the vallate papillae.

How you can test the Glossopharyngeal nerve? The ‘gag reflex’ is tested by touching the back of the throat by the tongue depressor. Glossopharyngeal nerve lesion characterized by : dysphonia, dysphagia and absence of the gag reflex.

Vagus (X) Cranial Nerve Type: mixed nerve. It contains motor, parasympathetic and sensory fibers. Fiber Contents and their Origin: 1. Motor fibers: from the nucleus ambiguus in the medulla and contains the fibers of the cranial accessory nerve. 2. Parasympathetic fibers: from the dorsal motor nucleus of the vagus in the medulla. It supplies the smooth muscles and glands of the thoracic and abdominal viscera till the left colic flexure. 3. Sensory fibers: from the 2 ganglia of the vagus and carry the following sensations: Taste sensation from the most posterior part of the tongue and epiglottis to nucleus solitarius General sensation from thoracic & abdominal viscera except the hindgut to nucleus solitarius

Exit from the Brain: in the postolivary fissure (between the olive and the inferior cerebellar peduncle). Exit from the Skull: through the jugular foramen. Course: the carotid sheath between the internal jugular vein and internal and common carotid arteries Distribution:It is distributed till the right 2/3 of the transverse colon.

Course In the neck : descends inside the carotid sheath between internal jugular vein and internal carotid artery (above) and bet. I.J.V. AND C.C.A. (below ) In the thorax : descends on the side of the trachea, then behind the bronchus, then along the esophagus In the abdomen :the Rt. Vagus runs behind the stomach, and the Lt. Vagus runs in front of the stomach

Branches and Distribution of the Vagus Nerve: 1. Meningeal branch: from the superior ganglion to the dura mater of the posterior cranial fossa. 2. Auricular branch: supplies a. The posterior wall and floor of the external auditory meatus. b. The outer surface of tympanic membrane. c. Skin of the outer surface of the auricle (concha). 3. Pharyngeal branch: forms the motor root of the pharyngeal plexus. It supplies: a. All muscles of the pharynx except the stylopharyngeus muscle. b. All muscles of the palate except the tensor palati muscle.

4. Superior laryngeal nerve: divides into two laryngeal branches (one motor and one sensory): a. External laryngeal nerve (motor): supplies the cricothyroid muscle. b. Internal laryngeal nerve (sensory): supplies the mucous membrane of the larynx above the vocal cord. 5. Recurrent laryngeal nerve: supplies: a. All muscles of the larynx except the cricothyroid muscle (motor). b. The mucous membrane of the larynx below the vocal cord (sensory). 6. Cardiac branches: 2 or 3 to the cardiac plexuses.

How you can test the Vagus nerve? Hypoglossal : Towards Vagus : Away 2- The person is asked to speak to check the voice for hoarsness. 3-Test for swallowing

Vagus nerve damage: causes hoarseness or loss of voice, impaired swallowing, GI dysfunction, blood pressure anomalies (with IX) . If both nerves are affected, it would be fatal.

11th CN: Accessory Nerve Type: motor nerve. Origin: by two roots Cranial Root: from the lower part of the nucleus ambigus in the medulla. It emerges from the postolivary fissure. 2. Spinal Root: from the upper 5 or 6 cervical segments of the spinal cord. It enters the cranial cavity through the foramen magnum.

Course:  The 2 roots unite at the jugular foramen, then the cranial root separates from the spinal root and joins the vagus nerve.  The spinal root crosses the posterior triangle parallel to the levator scapulae muscle to reach the trapezius muscle.

Distribution: 1. Cranial Root: it is distributed through the pharyngeal and recurrent laryngeal branches of the vagus to muscles of the pharynx (except stylopharyngeus), palate (except tensor palati) and larynx (except cricothyroid). It is now believed that fibers of the cranial root of the accessory nerve form the recurrent laryngeal branch of the vagus nerve. 2. Spinal Root: supplies the sternomastoid and trapezius muscles. Paralysis causes inability to shrug the shoulder.

Function: Movements of the soft palate, larynx, pharynx. Controls the movements of neck

Lesion Lesion results into: Difficulty in swallowing and speech Inability to turn the head Inability to shrug (raise) the shoulder Winging of scapula Remember : Long thoracic nerve Serratus anterior