Vagus nerve (CN X)
Nerve · CN X Mixed Parasympathetic
The longest cranial nerve: from the nucleus ambiguus (motor), dorsal motor nucleus (parasympathetic) and solitary nucleus (visceral sensation) it leaves through the jugular foramen, descends in the carotid sheath between the internal jugular vein and the carotid artery, gives the pharyngeal, superior laryngeal and recurrent laryngeal branches, and continues through the thorax and abdomen. Motor to the soft palate, pharynx and larynx; parasympathetic to the heart, lungs and gut as far as the splenic flexure.
Traced from the start
- Medulla oblongata
- Vagus nerve (CN X)
Detail
- Motor
- All muscles of the soft palate except tensor veli palatini (V3), all pharyngeal constrictors and muscles except stylopharyngeus (IX), and all intrinsic laryngeal muscles (superior and recurrent laryngeal branches)
- Parasympathetic
- Slows the sinoatrial and atrioventricular nodes, constricts bronchi and increases secretions, drives motility and secretion from the oesophagus to two-thirds of the way along the transverse colon
- Sensory
- Larynx, pharynx, external auditory meatus and tympanic membrane (auricular branch), thoracic and abdominal viscera, taste from the epiglottis
- Reflexes
- Efferent limb of the gag reflex; afferent and efferent limbs of the cough reflex and the baroreflex output to the heart
When it goes wrong
Unilateral vagal or nucleus ambiguus lesion (jugular foramen tumour, lateral medullary infarct, skull base fracture)
On saying 'ah' the palate rises only on the good side so the uvula deviates away from the lesion; nasal speech, nasal regurgitation of fluids, dysphagia, hoarseness and an absent gag on that side
Bilateral lesions of the vagal nuclei or nerves (motor neurone disease, brainstem stroke, Guillain–Barré)
Flaccid immobile palate, severe dysphagia with aspiration, absent gag and inability to cough effectively
Stimulation of the auricular branch (Arnold's nerve) by ear syringing, an ear foreign body or wax
Reflex cough, bradycardia or vasovagal syncope during the procedure; chronic cough that resolves when the ear canal is cleared
Carcinoma of the larynx, hypopharynx or piriform fossa
Referred otalgia via the auricular branch with a normal ear, sometimes the presenting complaint
Practise this structure
1 question in the bank tagged Vagus Nerve.