The vagus nerve is the 10th cranial nerve that has both motor and sensory components. It arises from the medulla and has an extensive distribution through the head, neck, thorax, and abdomen. It provides both parasympathetic output and visceral sensation. Some key functions include innervating the pharynx, larynx, heart, lungs, esophagus and stomach. Lesions can cause hoarseness of voice, dysphagia, or loss of gag reflex depending on the location along the nerve.

1. Vagus Nerve
By Dr. Piyush (MBBS, MD)

2. Answer Any cranial nerve under following headings:
• Introduction
• Functional components
• Formation
• Course
• Branches
• Distribution: Motor + Sensory
• Applied:
• Tests of integrity
• Lesion

3. Introduction
• 10th cranial nerve
• MIXED mainly motor
• Wanderer nerve: extensive distribution (H&N, thorax &
abdomen)
• Major Parasympathetic path.

7. Functional components
• SVE (Branchiomotor): Nucleus Ambiguus
• GVE (parasympathetic): Dorsal nucleus of Vagus
• GVA (viscerosensory): Nucleus Tractus Solitarius / DNV
• SVA (gustatory): Nucleus Tractus Solitarius
• GSA (somatosensory): Spinal nucleus of trigeminal

9. Formation
• Approx 10. rootlets from lateral aspect of medulla.
• Between olive and inferior cerebellar peduncle
• Between rootlets of IX and XIth nerve.
• Rootlets unite to form vagal nerve trunk.

12. COURSE
• Arises from lateral aspect of medulla.
• leaves cranial cavity through intermediate compartment of
Jugular foramen.
• 2 ganglia:
• Superior ganglion (Jugular): small - present in jugular
fossa
• Inferior ganglion (Nodose): large
• Runs downward in carotid sheath

15. • @ root of neck enters thorax
• Rt side: front of Rt subclavian artery
• Lt side: between lt common carotid & Lt subclavian
artery.

17. • In thorax:
• passes behind respective lung roots
• Rt vagus behind oesophagus (posterior vagal trunk)
• Lt vagus in front of oesophagus (Anterior vagal trunk)
• Crosses diaphragm via oesophageal opening.
• In abdomen:
• vagal trunks divide into terminal branches.

21. Branches:
• in neck:
• auricular branch
• Meningeal branch
• Pharyngeal branches
• Superior laryngeal nerve: split in external & internal
• Right Recurrent laryngeal nerve
• Superior and inferior cervical cardiac branches

23. • In thorax:
• Left recurrent laryngeal nerve
• Cardiac branches
• oesophageal branches
• In abdomen:
• gastric branches
• Hepatic branches
• Coeliac branch

28. DIstribution
Motor
• Pharyngeal branches: muscles
of pharynx & soft palate
• External laryngeal: supplies
cricothyroid
• Recurrent laryngeal: intrinsic
muscles of larynx
• Cardiac branches:
parasympathetic &
cardioinhibitory
Sensory
• Auricular : posterior part of
external ear and external
auditory canal.
• Meningeal: dura of
posterior cranial fossa
• Internal laryngeal:
laryngopharynx and upper
larynx

29. Motor
• oesophageal branches
• Gastric branches
• hepatic branches
• coeliac branches

30. Applied
• Tests of integrity of nerve:
• Subject is ask to open Mouth and say “AA” (आ): Checking
for Palatal palsy
• Gag re
fl
ex

34. • Lesions:
• Lower lesions: RLN palsy
• Hoarseness of voice
• Cadaveric position of vocal cord (paramedian)
• Higher lesions: RLN palsy + palatal palsy
• nasal regurgitation
• Dysphagia
• loss of gag & cough re
fl
ex

36. • The Alderman nerve phenomenon: auricular branch
behind ear was stimulated to improve loss of appetite.
• Vagotomy in peptic ulcer cases.
• Vagal nerve stimulation device implantation for
management of refractory epileptic seizures.

40. thank you