vagus nerve anatomy

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