7. • Trigeminal or fifth cranial nerve is the largest of the cranial nerves.
• It is a mixed nerve that consists primarily of sensory neurons.
Sensory nerve Face
Motor nerve Muscles of masticaion & several small muscles
• Lies in the floor of the middle cranial fossa, on the petrous temporal
bone.
• It is called trigeminal because it consists of 3 divisions the
ophthalmic nerve (V1), the maxillary nerve (V2), and the
mandibular nerve (V3).
• It forms the trigeminal ganglion from which its three branches
diverge.
The trigeminal ganglion corresponds to the dorsal root ganglion
of a spinal nerve.
8.
9. Trigeminal Nerve Nuclei
• The trigeminal nerve has four nuclei:
• 1.Main Sensory Nucleus
• The main sensory nucleus lies in the posterior part of the pons, lateral to
the motor nucleus . It is continuous below with the spinal nucleus.
• 2.Spinal Nucleus
• The spinal nucleus is continuous superiorly with the main sensory nucleus
in the pons and extends inferiorly through the whole length of the
medulla oblongata and into the upper part of the spinal cord as far as the
second cervical segment
• 3.Mesencephalic Nucleus
• it composed of a column of unipolar nerve cells situated in the lateral part
of the gray matter around the cerebral aqueduct
• 4.Motor Nucleus
In the pons medial to the main sensory nucleus
11. Sensory Components of the
Trigeminal Nerve
• The sensations of pain, temperature, touch, and pressure from the skin of the face
and mucous membranes travel along axons whose cell bodies are situated in the
trigeminal sensory ganglion .
• The central processes of these cells form the large sensory root of the trigeminal
nerve.
• The ascending branches terminate in the main sensory nucleus, and the
descending branches terminate in the spinal nucleus.
• The sensations of touch and pressure are conveyed by nerve fibers that terminate
in the main sensory nucleus. The sensations of pain and temperature pass to the
spinal nucleus
• The sensory fibers of V1 division terminate in the inferior part of the spinal
nucleus; the maxillary division in the middle and the mandibular division in the
superior part .
• Proprioceptive impulses from the muscles of mastication and from the facial and
extraocular muscles are carried by fibers in the sensory root of the trigeminal
nerve that have bypassed the semilunar or trigeminal ganglion .
12. • The axons of the neurons in the main sensory
and spinal nuclei and the central processes of
the cells in the mesencephalic nucleus now
cross the median plane and ascend as the
trigeminal lemniscus to terminate on the
nerve cells of the ventral posteromedial
nucleus of the thalamus.
• The axons of these cells now travel through
the internal capsule to the postcentral gyrus
(areas 3, 1, and 2) of the cerebral cortex.
13. Motor Component of the Trigeminal
Nerve
• The motor nucleus receives corticonuclear fibers from both
cerebral hemispheres . It also receives fibers from the
reticular formation, the red nucleus, the tectum,and the
medial longitudinal fasciculus. The cells of the motor nucleus
give rise to the axons that form the motor root.
• The motor nucleus supplies the muscles of mastication, the
tensor tympani, the tensor veli palatini, and the mylohyoid
and the anterior belly of the digastric muscle.
14. Course of the Trigeminal Nerve
• The trigeminal nerve leaves the anterior aspect of the pons as a small
motor root and a large sensory root. The nerve passes forward out of the
posterior cranial fossa and rests on the upper surface of the apex of the
petrous part of the temporal bone in the middle cranial fossa.
• The large sensory root now expands to form the crescent-shaped
trigeminal ganglion, which lies within a pouch of dura mater called the
trigeminal or Meckel cave. The ophthalmic, maxillary, and mandibular
nerves arise from the anterior border of the ganglion . The ophthalmic
nerve (V1) contains only sensory fibers and leaves the skull through the
superior orbital fissure to enter the orbital cavity.
• The maxillary nerve (V2) also contains only sensory fibers and leaves the
skull through the foramen rotundum.
• The mandibular nerve (V3) contains both sensory and motor fibers and
leaves the skull through the foramen ovale.
15. • The trigeminal ganglion (or Gasserian ganglion, or semilunar
ganglion) is a sensory ganglion of the trigeminal nerve (CN V)
that occupies a cavity (Meckel's cave) in the dura mater,
covering the trigeminal impression near the apex of the petrous
part of the temporal bone.
16. Three major branches emerge from the trigeminal ganglion and each branch
innervates a different dermatome :
1. The ophthalmic nerve (VI) passes along the side of the cavernous sinus to pass
into the orbit through the superior orbital fissure.
2. The maxillary nerve (V2) passes along the lateral wall of the cavernous sinus to
leave the skull through the foramen rotundum in the sphenoid bone.
3. The mandibular nerve (V3) passes out of the skull through the foramen ovale.
17. • Motor part supplies the 4 muscles of mastication ,
mylohyoid , anterior belly of digastric , tensor palati and
tensor tympani .
• Sensory part carries sensations from the scalp, face , teeth ,
gums and anterior two third of tongue.
18. Dermatome of Head & Neck
OPHTHALMIC NERVE :
1. Cornea
2. Skin of forehead
3. Scalp
4. Eyelids and nose
5. Mucous membranes of paranasal sinuses and nasal cavity
6. tentorium cerebelli
MAXILLARY NERVE :
1. Skin of the face over maxilla
2. Teeth of the upper jaw
3. Mucous membrane of the nose, the maxillary sinus and
palate
4. Meninges ACF ,MCF
MANDIBULAR NERVE :
1. Skin of cheek
2. Skin over mandible and side of head
3. Teeth of lower jaw and TMJ
4. Mucous membrane of mouth and anterior part of tongue
5. Meninges acf anf mcf
19. Ophthalmic Nerve - CN ( V1)
• Origin: Anterior aspect of the pons
• Opening to the Skull: Superior orbital fissure
• It has 3 main branches :
* Frontal
* Nasociliary
* Lacrimal
meningeal
20. Maxillary Nerve: CN V2
• Origin: Anterior aspect of the pons
• Opening to the Skull: Foramen rotundum
• Compostion: sensory
Infraorbital foreman
21. It is divided into four groups :
1. Cranium : Middle meningeal (meninges of ant and
middle cranial fossa)
1. In the Pterygopalatine Fossa : Zygomatic,
Sphenopalatine, Posterior superior alveolar.(upper
lip,teeth and gums,palate and nasopharynx)
2. In the Infraorbital Canal : Anterior superior alveolar,
Middle superior alveolar.(cheek)
3. On the Face : Inferior palpebral, External nasal,
Superior labial.( lateral forhead)
22. Mandibular Nerve
• It is the largest of the 3 divisions of trigeminal
nerve.
• It is the nerve of the first branchial arch.
• Opening to the Skull: Foramen Ovale
• Composition : Mixed nerve.
• After exit from foramen ovale it(nervous
spinosus) re-enters the skull through
f.spinosum.run with MMA supply meninges of
and ant. And middle cranial fossa
• Give ant. branch buccal nerve.
• Post.branch lingual and auriculotemporal nerve
and inf alveolar
23. Mental
Foramen
innervates the mucosa of the mouth and gums.
innervates the external auditory
meatus and portions of the
external surface of the tympanic
membrane.
provides general sensation to the anterior 2/3 of the tongue
innervate the lower teeth and gums. chin and lower lip
nerve to the masseter m , temporalis m.,
medial and lateral pterygoids, tensor palati
and tensor tympani.
anterior belly of the
digastric muscle.
V3
27. Corneal reflex
• Light touching of the cornea results in blinking of
the eyelids. Afferent impulses from the cornea or
conjunctiva travel through the v1 division of the
trigeminal nerve to the sensory nucleus of the
5th nerve
• Internuncial neurons connect with the motor
nucleus of the 7th on both sides through the
medial longitudinal fasciculus. 7th supply the
orbicularis oculi muscle causes closure of the
eyelids.
28. • Visual Body Reflexes
• The automatic scanning movements of the eyes and head that
are made when reading,the automatic movement of the eyes,
head, and neck toward the source of the visual stimulus, and
the protective closing of the eyes and even the raising of the
arm for protection are reflex actions .
• The visual impulses follow the optic nerves, optic chiasma,
and optic tracts to the superior colliculi. Here, the impulses
are relayed to the tectospinal and tectobulbar tracts and to
the neurons of the anterior gray columns of the spinal cord
and cranial motor nuclei.
30. • Trigeminal neuralgia ( tic douloureux ) is a
sensory disorder of CN V that is characterized
by sudden attacks of excruciating, intense
,burning or shock-like facial pain that lasts
from few seconds to several minutes and can
be physically and mentally incapacitating.
• The maxillary nerve is most frequently
involved, then the mandibular nerve, and least
frequently the ophthalmic nerve.
Trigeminal Neuralgia
31. • The pain is initiated by touching a sensitive
trigger zone of the skin.
• Most cases are still referred to as idiopathic,
although many are associated with vascular
compression of the trigeminal nerve.(most
common by SCA
32. • Also called the lateral medullary syndrome is a
classic clinical demonstration of the anatomy
of the fifth nerve.
• A stroke usually affects only one side of the
body. If a stroke causes loss of sensation, the
deficit will be lateralized to the right side or
the left side of the body. The only exceptions
to this rule are certain spinal cord lesions and
the medullary syndromes .
Wallenberg Syndrome
33. • In Wallenberg syndrome, a stroke causes loss
of pain/temperature sensation from one side of
the face and the other side of the body.
• The explanation involves the anatomy of the
brainstem. In the medulla, the ascending
spinothalamic tract (which carries
pain/temperature information from the
opposite side of the body) is adjacent to the
descending spinal tract of the fifth nerve
(which carries pain/temperature information
from the same side of the face).
34. • A stroke that cuts off the blood supply to this
area destroys both tracts simultaneously.
• The result is loss of pain/temperature
sensation (but not touch/position sensation) in
a unique “checkerboard” pattern (ipsilateral
face, contralateral body) that is entirely
diagnostic.
35. Clinical evaluation of CN V
• The sensory function is tested by asking the patient to close his
or her eyes and respond when feeling a touch,pain,temp
• Compare peri oral to post.face to exclude onion skin pattern
• A piece of guaze or test tubes filled with warm and cold fluid
are applied to one cheek and then to the corresponding
position on the other side. The testing is then repeated with
gentle touch of a sharp pin alternating sides.
• Define 1)organic or inorganic 2)which modality 3)distribution
36. • The motor function is tested by asking the
patient to open the mouth against resistance . Action of both
pterygoid muscles keeps the open jaw in the midline. If
pterygoid muscles of one side is paralysed , the jaw is deviated
to the paralysed side ( Pterygoid muscles of one side pushes
the jaw to the opposite side normally ).
• bulk and power of masseter and pterygoids by palpation when
clinching of jaw
• For deviation draw line in midline of upper and lower lip
• Inability to close the mouth (dangling jaw) suggest
MND,myopathy
• Tensor tympani paralysed-difficulty in hearing high notes
40. Component: Mixed
Origin : lower pons
Opening to the Skull: Internal acoustic meatus, facial canal, stylomastoid foramen
Function:
Motor
o muscles of the face and scalp
o Stapedius muscle
o Posterior belly of digastric
o Stylohyoid muscles
Sensory
o Taste from ant. 2/3 of tongue, from the floor of the mouth and palate
Secretomotor
o Submandibular and sublingual salivary glands
o Lacrimal gland
o Glands of nose and palate
41.
42. • Facial Nerve Nuclei
• The facial nerve has three nuclei: (1) the main motor nucleus, (2) the parasympathetic
• nuclei, and (3) the sensory nucleus.
• Main Motor Nucleus
• The main motor nucleus lies deep in the reticular formation of the lower part of the
• pons . The part of the nucleus that supplies the muscles of the upper part
• of the face receives corticonuclear fibers from both cerebral hemispheres. The part of
• the nucleus that supplies the muscles of the lower part of the face receives only
• corticonuclear fibers from the opposite cerebral hemisphere.
• These pathways explain the voluntary control of facial muscles. However, another
involuntary pathway exists; it is separate and controls mimetic or emotional changes in
facial expression. This other pathway forms part of the reticular formation .
• Parasympathetic Nuclei
• Parasympathetic nuclei lie posterolateral to the main motor nucleus. They are the
superior salivatory and lacrimal nuclei . The superior salivatory nucleus
receives afferent fibers from the hypothalamus through the descending autonomic
pathways. Information concerning taste also is received from the nucleus of the
solitary tract from the mouth cavity.
43. • Sensory Nucleus
• The sensory nucleus is the upper part of the nucleus of the tractus
solitarius and lies close to the motor nucleus . Sensations of taste
travel through the peripheral axons of nerve cells situated in the
geniculate ganglion on the seventh cranial nerve.
• The central processes of these cells synapse on nerve cells in the
nucleus. Efferent fibers cross the median plane and ascend to the
ventral posterior medial nucleus of the opposite thalamus and to a
number of hypothalamic nuclei.
• From the thalamus, the axons of the thalamic cells pass through
the internal capsule and corona radiata to end in the taste area of
the cortex in the lower part of the postcentral gyrus
44.
45. Course of the Facial Nerve
• The facial nerve consists of a motor and a sensory root. The fibers of the motor root
first travel posteriorly around the medial side of the abducent nucleus .
• They then pass around the nucleus beneath the colliculus facialis in the floor of the
fourth ventricle and, finally pass anteriorly to emerge from the brainstem .
• The sensory root (nervus intermedius) is formed of the central processes of the
unipolar cells of the geniculate ganglion.
• The two roots of the facial nerve emerge from the anterior surface of the brain
between the pons and the medulla oblongata. They pass laterally in the posterior
cranial fossa with the vestibulocochlear nerve and enter the internal acoustic meatus in
the petrous part of the temporal bone. At the bottom of the meatus, the nerve enters
the facial canal and runs laterally through the inner ear. On reaching the medial wall of
the tympanic cavity, the nerve expands to form the sensory geniculate ganglion and turns
sharply backward above the promontory. At the posterior wall of the
tympanic cavity, the facial nerve turns downward on the medial side of the aditus of
the mastoid antrum, descends behind the pyramid, and emerges from the stylomastoid
foramen
46. Branches within facial canal :
1. Greater petrosal nerve
2. Nerve to the stapedius
3. Chorda tympani
Branches immediately below the stylomastoid foramen :
1. Posterior auricular
2. Diagastric
3. Stylohyoid
Branches within the parotid gland :
1. Temporal
2. Zygomatic
3. Buccal
4. Mandibular
5. Cervical
BRANCHES OF FACIAL NERVE
50. Facial palsy
• Facial palsy is due to the paralysis of facial nerve.
• It is of 2 types – * Upper motor neuron type
* Lower motor neuron type
• Upper motor neuron facial palsy is due to the involvement of
corticonuclear fibers.
• It is also called as supranuclear type of palsy.
• It leads to paralysis of the contralateral lower part of face below the
palpebral fissure.
51. • The upper part of face is spared because the part of the
facial nucleus which supplies it, is innervated by
corticonuclear fibers from both the cerebral hemispheres.
• Lower motor neuron palsy is of 2 types :
1. Nuclear paralysis - due to involvement of nucleus of
facial nerve, the motor nucleus of facial nerve is close to
the abducens nerve which is also usually affected, it
leads to paralysis of muscles of the entire face on
ipsilateral side.
2. Infranuclear paralysis : This occurs due to involvement
of facial nerve.
52. Bell’s Palsy
• Is a lower motor neuron type of facial nerve
involvement.
• It has varied etiology eg : exposure to sudden cold,
middle ear infections.
• It leads to paralysis of muscles of facial expression.
Bell's palsy is a type of facial paralysis that results in
an inability to control the facial muscles on the
affected side. They may include muscle twitching,
weakness, or total loss of the ability to move one or
rarely both sides of the face. Other symptoms
include drooping of the eyelid, a change in taste,
pain around the ear, and increased sensitivity to
sound.
53.
54. Millard Gubler Syndrome(venral pontine
syndrome)
• Abducens nerve palsy on the ipsilateral
side leads to diplopia,int.strabismus
• Infra nuclear type of facial nerve palsy
leads flacid paralysis of fascial muscles
with loss of corneal reflex
• Contra lateral hemiplegia due to
involvement of corticospinal tract
55. Raymond Foville Syndrome
• Due to blockage of basilar artery,in the
region of pons
• Paralysis of conjugate occular deviation to
same side of lesion due to pprf infarct
• Contralateral hemiplegia, infra nucleus
facial nerve palsy,6th nerve palsy on the
same side
56. Ramsay Hunt Syndrome
• Re activation of herpes zoster in geniculate
ganglion
• Triad of I/L facial paralsis,ear pain,vesicles on
the face or ear is typical presentation
• Also called herpes zoster oticus
• Facial nerve injured by forceps delivery,
fracture of skull, tumour, middle ear infection.
57. Injury of Zygomatic branch of CN VII
• Leads to paralysis, loss of tone of
orbicularis oculi, in the lower eyelid thus
the lower eye lid drops.
• As a result, tears do not spread over the
cornea and the dry cornea ulcerates –
results in corneal scar – impairs vision.
58. Paralysis of Buccal branch
• It prevents the emptying of food from the
vestibule of the cheeks.
• The food lodges in the vestibule and
cannot be maintained in position between
the teeth for chewing.
59. Paralysis of Marginal mandibular branch of CN
VII
• This may occur when an incision is made
along the inferior border of the mandible.
• Injury to this branch results in an
unslightly drooping of the corner of the
mouth.
61. Clinical evaluation of Facial nerve
Tested by checking the facial muscles :
1. FRONTALIS: Ask the patient to look upward
without moving his head and look for normal
horizontal wrinkles of the forehead.
2. ORBICULARIS OCULI: Tight closure of eyes.
3. ORBICULARIS ORIS: whistling and pursing
the mouth.
62. 4. DILATOR OF MOUTH: Showing the
teeth.
5. BUCCINATOR: Puffing the mouth and
then blowing forcibly.
6. PLATYSMA: Forcible pulling of the
angle of the mouth downwards and
backwards forcing vertical folds of skin
on the side of the neck.
63. • Taste on each half of the anterior two
thirds of the tongue can be tested with
sugar, salt, vinegar and quinine for sweet,
salt, sour and bitter sensation.
65. • Other Names : Auditory / Acoustic Nerve
• Component : Sensory
• Function:
o Vestibular – saccule,scc-Balance, position of head
o Cochlear – Organ of Corti – Hearing
• Origin:pons
• Opening to the Skull: Internal acoustic meatus
68. Vestibular Nerve
• The vestibular nerve conducts nerve impulses from
the utricle and saccule that provide information
concerning the position of the head; the nerve also
conducts impulses from the semicircular canals
that provide information concerning movements of
the head.
• The nerve fibers of the vestibular nerve are the
central processes of nerve cells located in the
vestibular ganglion, which is situated in the
internal acoustic meatus.
• They enter the anterior surface of the brainstem in
a groove between the lower border of the pons
and the upper part of the medulla oblongata
69. • The Vestibular Nuclear Comple
• Four nuclei may be recognized:
• (1) the lateral vestibular nucleus,
• (2) the superior vestibular nucleus,
• (3) the medial vestibular nucleus, and
• (4) the inferior vestibular nucleus
70. • The vestibular nuclei receive afferent fibers from the utricle and
saccule and the semicircular canals through the vestibular nerve
and fibers from the cerebellum through the inferior cerebellar
peduncle
• .Efferent fibers from the nuclei pass to the cerebellum through the
inferior cerebellar peduncle also descend uncrossed to the spinal
cord from the lateral vestibular nucleus and form the
vestibulospinal tract In addition, efferent fibers pass to the nuclei
of the 3,4,6 nerve through MLF
• These connections enable the movements of the head and the eyes
to be coordinated
• so that visual fixation on an object can be maintained. In addition,
information received from the internal ear can assist in maintaining
balance by influencing the muscle tone of the limbs and trunk.
71. • ascending fibers also pass upward from the
vestibular nuclei to the cerebral cortex to
• the vestibular area in the postcentral gyrus
just above the lateral fissure.
• These fibers are thought to relay in the ventral
posterior nuclei of the thalamus. The cerebral
cortex
• probably serves to orient the individual
consciously in space.
73. • Cochlear Nerve
• The cochlear nerve conducts nerve impulses concerned with sound
from the organ of Corti in the cochlea. The fibers of the nerve enter
the anterior surface of the brainstem at the lower border of the
pons on the lateral side of the emerging facial nerve and are
separated from it by the vestibular nerve
• Cochlear Nuclei
• The anterior and posterior cochlear nuclei are situated on the
surface of the inferior cerebellar peduncle . They receive afferent
fibers from the cochlea through the cochlear nerve. The cochlear
nuclei send axons (second-order neuron fibers) that run medially
through the pons to end in the trapezoid body and the olivary
nucleus.
74. • Here, they are relayed in the posterior nucleus of the trapezoid body and the
superior olivary nucleus on the same or the opposite side. The axons now ascend
through the posterior part of the pons and midbrain and form a tract known as
the lateral lemniscus .
• Each lateral lemniscus, therefore, consists of third-order neurons from both
sides.
• On reaching the midbrain, the fibers of the lateral lemniscus either terminate in
the nucleus of the inferior colliculus or are relayed in the medial geniculate body
and pass to the auditory cortex of the cerebral hemisphere through the acoustic
radiation of the internal capsule
• The primary auditory cortex (areas 41 and 42) includes the gyrus of Heschl on the
upper surface of the superior temporal gyrus. The recognition and interpretation
of sounds on the basis of past experience take place in the secondary auditory
area..
75. Course of the vestibulocochlear Nerve
• The vestibular and cochlear parts of the nerve
leave the anterior surface of the brainbetween
the lower border of the pons and the medulla
oblongata .
• They run laterally in the posterior cranial fossa
and enter the internal acoustic meatus with
the facial nerve. The fibers are the distributed
to the different parts of the internal ear
77. Clinical examination
• History and observation
• Whispered voice has been recommeded as a screening test
for hearing assesment
• Finger rub test-bedside
• Stethoscope –earpiece and chest piece
• Ross’ method-6 ft whisper and compare
• CALFRAST TEST-70 cm soft rub soundSchwabach tuning fork
test-compare AC,BC with examiner self
• Rinne and weber test
78. Vestibular fuction
Vestibulospinal reflex
• past pointing
• romberg’s test,
• Tandem gait
• Tandem romberg’s test
• Star walking test
VOR
• Oculocephalic test(doll’s eye test)
• Head thrust
• Dynamic visual acuity
• Caloric tesr(COWS)
• nystagmus
79. Causes of hearing loss
Conductive type
• ext,.auditory canal obstruction
• Perforation of T.M
• Middle ear dis.
• Nasopharynx dis.causing blocked eustachian tube
SNHL
• DIS. Of cochlea –acoustic trauma,meniers dis,infection,presbycusis
• DIS. Of cochlear nerve or nuclei-trauma,tumour,infection or toxin
83. • Other Name : Hering ’s nerve
• Component : Mixed
• Origin: Medulla oblongata
• Opening to the Skull: Jugular foramen
• Function:
• Motor
Stylopharyngeus muscle – assists swallowing
• Sensory
Pharynx
Carotis sinus and carotid body
Gustatory :-
Posterior one third of tongue including circumvallate papillae.
• Secretomotor
Parotid gland
84. Glossopharyngeal Nerve Nuclei
• The glossopharyngeal nerve has three nuclei: (1) the main motor nucleus, (2)
the parasympathetic nucleus, and (3) the sensory nucleus
• Main Motor Nucleus
• The main motor nucleus lies deep in the reticular formation of the medulla
oblongata and is formed by the superior end of the nucleus ambiguus . It
receives corticonuclear fibers from both cerebral hemispheres. The efferent
fibers supply the stylopharyngeus muscle.
• Parasympathetic Nucleus
• The parasympathetic nucleus is also called the inferior salivatory nucleus
• It receives afferent fibers from the hypothalamus through the descending
autonomic pathways. It also is thought to receive information from the
olfactory system through the reticular formation. Information concerning taste
also is received from the nucleusof the solitary tract from the mouth cavity.
• The efferent preganglionic parasympathetic fibers reach the otic ganglion
through the
• tympanic branch of the glossopharyngeal nerve, the tympanic plexus, and the
lesser
• petrosal nerve . The postganglionic fibers pass to the parotid salivary
• gland
85. • Sensory Nucleus
• The sensory nucleus is part of the nucleus of the tractus solitarius .
Sensations of taste travel through the peripheral axons of nerve cells situated in the
ganglion on the glossopharyngeal nerve. The central processes of these cells synapse on
nerve cells in the nucleus.
• Efferent fibers cross the median plane and ascend to the
ventral group of nuclei of the opposite thalamus and a number of hypothalamic nuclei.
• From the thalamus, the axons of the thalamic cells pass through the internal capsule
and corona radiata to end in the lower part of the postcentral gyrus.
• Afferent impulses from the carotid sinus, a baroreceptor situated at the bifurcation of
the common carotid artery, also travel with the glossopharyngeal nerve. They terminate
in the nucleus of the tractus solitarius and are connected to the dorsal motor nucleus
of the vagus nerve. The carotid sinus reflex that involves the glossopharyngeal and
vagus nerves assists in the regulation of arterial blood pressure
86. Course of the Glossopharyngeal
Nerve
• Course of the Glossopharyngeal Nerve
• The glossopharyngeal nerve leaves the anterolateral surface of the upper part of the
medulla oblongata as a series of rootlets in a groove between the olive and the inferior
• cerebellar peduncle ).
• It passes laterally in the posterior cranial fossa and leaves the skull through the jugular
foramen.
• The superior and inferior glossopharyngeal sensory ganglia are situated on the nerve here.
The nerve then descends through the upper part of the neck in company with the internal
jugular vein and the internal carotid artery to reach the posterior border of the
stylopharyngeus muscle, which it supplies.
• The nerve then passes forward between the superior and middle constrictor
muscles of the pharynx to give sensory branches to the mucous membrane of the
pharynx and the posterior third of the tongue .
87. 1. Communicating branch
- a twig to the ganglion of vagus nerve
- a twig to auricular branch of vagus
nerve.
2. Tympanic branch
- Lesser petrosal nerve - carry pre-ganglionic
parasympathetic secretomotor fibres to parotid
gland .
- twigs to tympanic cavity, auditory
tube
Branches of Glossopharyngeal nerve
88. 3. Carotid branch – supplies the carotid sinus
4. Pharyngeal branch - form plexus with
branches of vagus and sympathetic .
5. Branch to stylopharyngeus
6. Tonsillar branches - tonsil and soft palate
7. Lingual branches - taste and general sensation
from posterior one third of tongue .
91. • Complete lesion of the glossopharyngeal nerve
results in the following :
1. Loss of taste and common sensations over the
posterior one third of the tongue.
2. Difficulty in swallowing
3. Loss of salivation from the parotid gland
4. Unilateral loss of gag reflex
• Complete lesion of glossopharyngeal nerve is
rare in isolation. There is often involvement of
vagus nerve.
92. Glossopharyngeal Neuralgia
• It is known as tic douloureux of CN IX or
Cranial mononeuropathy IX .
• It is a condition in which there are repeated
episodes of severe pain in the tongue, throat, ear
and tonsils which can last from few seconds to
few minutes.
• It is believed to be caused by irritation of the
ninth cranial nerve.
93. • The sudden intensification of pain is of a burning or
stabbing nature.
• Paroxysms of pain are initiated by swallowing,
protruding the tongue, talking or touching the palatine
tonsil.
• Pain paroxysms occur during eating when trigger
areas are stimulated.
94. Clinical Evaluation Of
Glossopharyngeal Nerve
• Ninth nerve is tested by tickling the
posterior wall of pharynx. There is reflex
contraction of pharyngeal muscles called
gag reflex .
• In IX nerve paralysis there is no such
contraction.
97. • Vagus nerve is a mixed nerve.
• Containing approximately 80% sensory fibers.
• It supplies :
Organs of voice and respiration with both motor
and sensory fibres .
Pharynx (except stylopharyngeus), oesophagus,
stomach and heart with motor fibres.
One muscle of the tongue (palatoglossus).
The muscles of the soft palate (except tensor veli
palatini ).
• It is the most extensive cranial nerve, consisting
of many branches.
98. COURSE OF VAGUS NERVE
• The nerve runs from the lower brainstem through the
base of the skull to travel in the neck with the carotid
artery and jugular vein.
• It then penetrates the chest to travel to the heart and
lungs.
• It continues on to the abdomen where it breaks into a
network of nerves to the abdominal organs.
• Supplies motor and sensory parasympathetic fibres to
pretty much everything from the neck down to the first
third of the transverse colon.
99. • It is involved in, amongst other things, such as heart
rate, gastrointestinal peristalsis, sweating, and
speech (via the recurrent laryngeal nerve) and also
the controls a few skeletal muscle of the pharynx and
larynx:
Levator veli palatini muscle
Salpingopharyngeus muscle
Stylopharyngeus muscle
Palatoglossus muscle
Palatopharyngeus muscle
Superior, middle and inferior pharyngeal
constrictors
100.
101. CLINICALANATOMY OF VAGUS
NERVE
• Lesion Of Vagus Nerve Leads To :
Dysphagia
Hoarseness
Uvula points away from the affected side
Loss of gag and cough reflex
103. • Component: Motor
• Function:
Cranial root
o Muscles of soft palate (except tensor veli palatini)
o Muscles pharynx (except styopharyngeus)
o Muscles of larynx (except cricothyroid)
Spinal root
o Sternocleidomastoid
o Trapezius muscle
• Origin: Medulla oblongata
• Opening to the Skull: Jugular foramen
104. • The sternocleidomastoid muscle turns the head
and the trapezius muscle braces the shoulder
and rotates the scapula during elevation of the
upper limbs.
105. ASSESSING X & XI CRANIAL
NERVES
• CN X &XI can be assessed together by testing the
gag reflex, palatal movement and sensation.
– Touching the pharynx with an orange stick tests pharyngeal
sensation (9th nerve) and the gag reflex (9th and 10th
nerve). On phonation the soft palate should rise
symmetrically in the midline (10th nerve).
• CN XI can be tested by assessing the power of the
sternocleidomastoid and the trapezius muscles i.e.
turning the head and shrugging the shoulders.
106. APPLIED ANATOMY OF
ACCESSARY NERVE
• Lesion may result the followings :
Shoulder droop
Weakness turning head to opposite side
108. • Component : Motor.
• Supplies : Muscles of the tongue except the
palatoglossus
• Fibers arises : From the hypoglossal Nucleus
which lies in the Medulla, in the floor of the
fourth verticle
• Opening to the skull : Hypoglossal canal.
109.
110. • After coming out of the cranial cavity the nerve
lies deep to the internal carotid artery and the
ninth, tenth and eleventh cranial nerves.
• Finally the nerve ends by dividing into terminal
branches.
• Some fibers of the first cervical nerve join the
hypoglossal nerve and are distributed through its
branches.
111. BRANCHES OF HYPOGLOSSAL
NERVE
1. Muscular branches :
These are branches of the hypoglossal nerve proper and
supply all the muscles of the tongue expect
palatoglossus which is supplied by the cranial root of
accessory nerve via the pharyngeal plexus.
1. Branches of the Hypoglossal nerve containing
C1 fibers :
* Meningeal branch – It supplies the duramater of
posterior cranial fossa.
112. * Descendens hypoglossi or upper root of ansa
cervicalis – it arises from the nerve as it crosses the
internal carotid artery. It runs downwards to join the
inferior root of ansa cervicalis.
* Nerve to thyrohyoid
3. Nerve to geniohyoid
115. Injury to the Hypoglossal nerve
• The hypoglossal nerve
accompanies the tonsillar artery
on the laterial wall of the
pharynx and this wall is
vulnerable to injury during
tonsillectomy.
• Injury to CN twelve paralyses
the ipsilateral half of the tongue.
After some time the tongue
atrophies, making it appear
shrunken and wrinkled.
116. • When the tongue is protruded, its tip deviates
towards the paralysed side because of the
unopposed action of the genioglossus in the
normal side of the tongue.
117. Clinical Evaluation Of Hypoglossal
Nerve
• The hypoglossal nerve is
tested clinically by asking the
patient to protrude his tongue.
Normally the tongue is
protruded straight forward. If
the nerve is paralysed, the
tongue deviates to the
paralysed side.
