2. INTRODUCTION
• 10th cranial nerve
• So called due to its vague course through the head, neck, thorax and
• the abdomen. Derived from word vagrant/vague-k/c/a wandering nerve
• Longest nerve of the autonomic nervous system in the body
• MIXED NERVE: sensory, motor and parasympathetic
• Primarily associated with the parasympathetic division of the ANS
however, it also has some sympathetic influence through peripheral
chemoreceptors
• Associated with the derivatives of the fourth pharyngeal arch.
3. Origin and Nucleus
Within the medulla oblongata of the brainstem, there are 4
vagal nuclei, onto
which axons of the vagus nerve emerge from or converge
onto:
1. NUCLEUS AMBIGUOUS
(BRANCHIOMOTOR):
2. DORSAL MOTOR NUCLEUS
(PARASYMAPATHETIC)
3. NUCLEUS OF TRACTUS SOLITARIS:
(GUSTATORY)
4. NUCLEUS OF SPINAL TRACT OF TRIGEMINAL
4.
5.
6. GANGLIA ASSOCIATED
SUPERIOR/JUGULAR
LIES WITHIN THE JUGULAR FORAMEN
ROUNDED
SMALLER IN SIZE
Connected to IX, XI and to
Superior Cervical Ganglion
1.MENINGEAL
2.AURICULAR
INFERIOR/GANGLION NODASUM
BELOW THE JUGULAR FORAMEN-
NEAR THE SKULL BASE
CYLINDRICAL (2.5 cm)
LARGER
Joined by cranial root of XI; connected to
XII, superior cervical ganglion
1. PHARYNGEAL
2.CAROTID
3.SUPERIOR LARYNGEAL
4.RECURRENT LARYNGEAL 5.CARDIAC
8. INTRACRANIAL
Lateral aspect of
medulla;between olivary
nucleus and ICP
Nerve attached to 10
rootlets to Posterolateral
sulcus of medulla
Rootlets unite –Single trunk
Laterally across the jugular
tubercle along with IX, XI
Nerve is enclosed within the same dural sheath as the 11th
Nerve; 9th CN lies within a separate dural sheath.
10. • Rootlet join to form a single
trunk and pass laterally across
the juglar tubercle along with 9
and 10
• Leaves the cranial cavity through
middle part of juglar foramen
and in the foramen joined by
cranial root of accessory nerve
14. Right Vagus in front of
Right Subclavian Artery
Left Vagus between
left common carotid
and left subclavian
arteries
Enter the
Thorax
Root of the neck
19. 1. MENINGEAL BRANCH
Arises from
Superior Ganglion
Passes back
through Jugular
Foramen
Supplies duramater
of posterior cranial
fossa
SUPPLIES:
• Duramater of Posterior Cranial Fossa
20.
21. 2. AURICULAR/ARNOLD’S NERVE
Arises from
Superior
Ganglion
Re-enters the
lateral portion
of the jugular
foramen via
the mastoid
canaliculus
Exits again
through the
tympanomast
oid suture of
the temporal
bone
Reaches and
supplies the
skin.
SUPPLIES:
• Concha, root of the auricle
• posterior half of the external auditory meatus
• Tympanic membrane
22. 3. PHARYNGEAL
LOWER PART
OF INFERIOR
GANGLION
PASSES
BETWEEN
EXTERNAL AND
INTERNAL
CAROTID
ARTERIES
REACHES THE
MIDDLE
CONSTRICTOR
OF PHARYNX
FORMS THE
PHARYNGEAL
PLEXUS
Supplies:
• Muscles of pharynx(except the stylopharyngeus muscle)
• Muscles of soft palate (except tensor palatini muscle)
26. 4.SUPERIOR LARYNGEAL NERVE
Arise from
the inferior
ganglion of
the vagus
nerve.
Moves
forwards
on the
superior
constrictor
Passes
between the
external and
internal
carotid
arteries
At the tip of
the hyoid
bone, divides
into external
and internal
branches,
27.
28. A. EXTERNAL LARYNGEAL NERVE
Accompanies
the Superior
Thyroid
Artery
Pierces the
inferior
Constrictor
Supplies
CRICOTHYROID
Also branches to
inferior
constrictor +
pharyngeal plexus
All other intrinsic
laryngeal muscles
are innervated by
recurrent laryngeal
nerve
MOTOR
29. B. INTERNAL LARYNGEAL NERVE
Supplies the mucous membrane of larynx ABOVE the level of vocal cords
PASSES
DOWNWARDS
AND
FORWARDS
PIERCES
thyrohyoid
membrane
Enters the
larynx
SENSORY
30.
31. 5. INFERIOR/Recurrent laryngeal
nerve
Arises from
in front of
RIGHT
SUBCLAVIA
N ARTERY
Winds
backwards
below the
artery
Runs
upwards
behind
SUBCLAVIA
N AND
COMMON
CAROTID
ARTERIES
Reach the
trachea-
oesophagea
l groove;
related to
Inferior
Thyroid
Artery
Passses
deep to the
lower
border of
the
INFERIOR
CONSTRICT
OR
Enters
larynx
behind the
CRICOTHYR
OID JOINT
a. RIGHT RECURRENT LARYNGEAL
32.
33. Arises from
Vagus in the
thorax at the
level of aoa
Loops
around
Ligamentum
arteriosum
Reaches the
tracheooeso
phagal
groove
Usually
posterior to
the inferior
thyroid
artery
Supplies:
• Similar distribution as Right RL
Left recurrent laryngeal nerve
34.
35. AREAS
SUPPLIED
Recurrent
laryngeal
nerve
All intrinsic muscles of
larynx, except the
cricothyroid
Sensory nerves
to the larynx
below the level
of vocal cords
Cardiac branches
to the deep
cardiac plexus
Branches to trachea
and oesophagus
Inferior
constrictor
36. 6. Cardiac branches
branches
off :
Superior
and
Inferior
Total 4 :Out of which
the three go to the
deep cardiac plexus
Left inferior
goes to
superficial
cardiac
plexus
37.
38. Functional components
Specifically, the vagus nerve contains:
1. Special visceral efferent (motor) fibers.
2. General visceral efferent (motor) fibers
3. General visceral afferent (sensory) fibers
4. Special visceral afferent (sensory) fibers
5. General Somatic Afferent Fibres
39. • SENSORY FUNCTION
• There are somatic and visceral components to the sensory
function of the vagus nerve. (GSA AND GVA)
• Superior ganglion primarily conveys somatic sensation,
• Inferior ganglion relays general visceral sensation and taste.
• Somatic sensory portion conveys pain, temperature, and touch
sensation from the pharynx, larynx, ear canal, external surface
of the tympanic membrane, and meninges of posterior fossa.
40. Viscera sensation (GVA) is that from the organs of the body.
• Central processes terminate in the caudal portion of the solitary
tract.
• The vagus nerve innervates:
• Laryngopharynx – via the internal laryngeal nerve.
• Superior aspect of larynx (above vocal folds) – via the internal
laryngeal nerve.
• Heart – via cardiac branches of the vagus nerve.
• Gastro-intestinal tract (up to the splenic flexure) – via the
terminal branches of the vagus nerve
41. • Collaterals to reticular formation, DMNX, and other CN nuclei
mediate important visceral reflexes and are involved in the
regulation of cardiovascular, respiratory, and gastrointestinal
function.
• Special visceral afferent (SVA )- Vagus nerve has a minor role
in taste sensation.
• It carries afferent fibres from the root of tongue.
42. • MOTOR FUNCTION
• Vagus nerve innervates the majority of the muscles associated
with the pharynx and larynx.
• These muscles are responsible for the initiation of swallowing
and phonation
43. • PARASYMPATHETIC FUNCTION
• Vagus nerve is main parasympathetic outflow to the heart and
gastro-intestinal organs.
• Vagal discharge causes bradycardia, hypotension,
bronchoconstriction, bronchorrhea, increased peristalsis,
increased gastric secretion, and inhibition of adrenal function.
51. EXAMINATION OF
VAGUS NERVE:
▶ ASK THE PATIENT TO SAY AHH-The Vagus nerve is tested clinically by comparing the
palatal arches on the two sides. BEST METHOD
▶ On the paralysed side, there is no arching, and the uvula is pulled to the normal side.
▶CHECK FOR GAG REFLEX (AFFERENT – 9/EFFERENT 10)
▶CHECK FOR COUGH REFLEX
1. Nasal regurgitation
2. Nasal twang in voice
3. Hoarseness of voice
4. Flattening of the palatal arch
5. Cadaveric position of the vocal cord
6. Dysphagia
Paralysis of vagus nerve
52.
53.
54. ▶ Irritation of the auricular branch of vagus in the external ear
persistent cough, vomiting, or death (due to sudden cardiac inhibiton)
▶ Stimulation of the auricular branch increased appetite
▶ Irritation of the internal laryngeal nerve by enlarged lymph nodes
persistent cough
▶ Injury to recurrent laryngeal nerve hoarseness and dysphonia due
to paralysis of the vocal cord.
▶ Injury to pharyngeal nerve dysphagia.
55. ▶ Some fibres in the geniculate ganglion of facial
nerve pass into the vagus through communications
between the two nerves.
▶ They reach the skin of auricle through the auricular
branch of vagus.
▶ Sometimes a sensory ganglion may have a viral
infection and vesicles appear on the area of skin
supplied by the ganglion.-HERPES ZOSTER OTICUS
▶ In herpes zoster of the geniculate ganglion,
vesicles appear on the skin of auricle.
56. VAGAL NERVE STIMULATION
• ▶ A medical treatment that involves delivering electrical impulses
to the vagus
• ▶ Used as an adjunctive treatment for certain types of intractable
epilepsy and treatment-resistant depression.
• VAGOTOMY – done in pectic ulcer disease.No role in
h&n.
Vagus has two sensory ganglia.
1. Superior (jugular) vagal ganglion located in the jugular fossa
of the temporal bone;
2. Inferior (nodose) ganglion is located just distal to the jugular
foramen.
Strs passing in jugular foramen- 9,10,11 and junction of ijv and sigmoid sinus,emissary veins
From root of neck right vagus infront of right subclavian artery
And left vagus between left CCA and left subclavian arteries
Then both descend down to thorax
10 major terminal branches that arise at different levels:
• (a) meningeal, (b) auricular, (c) pharyngeal, (d) carotid, (e)
superior laryngeal, (f ) recurrent laryngeal, (g) cardiac, (h)
esophageal, (i) pulmonary, and (j) gastrointestinal.
EXT BR SUPPLIES CT AND INT BR PIERCES THYROHYOID MEM AND GIVES SENSORY SUPPLY TO LARYNX ND HYPOPHARYNX
Simons,lore triangle Simon's triangle
Classically, the RLN is identified intraoperatively in Simon’s triangle, which is formed by
the common carotid artery laterally,
the oesophagus medially, and
the inferior thyroid artery superiorly.
The nerve crosses the triangle.
Lore’s Triangle
This triangle described by Lore et al., is also for identification of recurrent laryngeal nerve.
Medial border of the triangle is formed by the trachea / esophagus,
the lateral border by carotid artery
and superior border by the surface of inferior pole of thyro
