2. • Work together to supply the musculature of the
pharynx (mostly supplied by CN 10) and
• Transmit visceral afferent information from
vascular baroreceptors.
• And each nerve also has additional individual
functions.
3. • They are difficult to isolate clinically.
• Commonly affected together since they both
communicate with nuclei in the dorsolateral
medulla.
• Both pass through the jugular foramen, and
they are adjacent throughout parts of the
neck.
4.
5. CN 9 supplies:
• One pharyngeal muscle: stylopharyngeus
• One gland: parotid
• One region of taste: posterior one third of the
tongue
• One region of visceral sensation: carotid body
• Three small regions of somatic sensation:
posterior one third of the tongue, pharynx
(shared with CN 10), middle ear, and external
auditory meatus (shared with CN 7 and CN 10
6.
7. The functions of CN 10 include:
• Motor supply to all muscles of the larynx and
pharynx except
tensor veli palitini (CN 5),
mylohyoid (CN 5),
stylohyoid (CN 7),
stylopharyngeus (CN 9)
• Motor supply to one muscle of the tongue:
palatoglossus (all others are innervated by CN 12)
8. Cont…
• Somatic sensation from:
• The dura matter of the posterior fossa aside
from the tentorium (the sensory innervation to
the rest of the dura including the tentorium is
supplied by CN 5)
• The pharynx (shared with CN 9)
• The external auditory meatus (shared with CN 7
and CN 9
9. Cont…
• Visceral sensation from the aortic arch
• Visceral parasympathetic efferent supply to and
afferent input from all of the viscera of the thorax
and abdomen
with the exception of the distal third of the GI
tract and genitourinary organs (which receive
their parasympathetic supply from sacral spinal
cord levels S2–S4).
• Taste in the pharynx
10.
11. There are several functions that are shared across
cranial nerves CNs 5, 7, 9, and 10,
12. Cont…
• The laryngeal and pharyngeal motor input to CN
9 and CN 10 comes from the nucleus ambiguus
in the dorsal medulla.
• Visceral motor supply that travels in CN 10
originates in the dorsal motor nucleus of the
vagus.
• Afferent visceral information arrives with taste
information to the nucleus solitarius.
13.
14.
15.
16. • Lesions of CN 10 can cause laryngeal and/or
pharyngeal weakness.
• Laryngeal weakness can lead to softer voice
(hypophonia), nasal voice,
and guttural dysarthria (difficulty producing
the consonants “G” and “K”).
• Pharyngeal weakness can cause difficulty
swallowing (dysphagia).
17. • On examination, CN 9 and CN 10 can be
assessed by evaluating palate elevation and gag
reflex.
• When there is unilateral palate weakness, the
palate droops on the weak side and is pulled
upward toward the stronger side.
• The gag reflex is mediated predominantly by CN
9 for the afferent limb (palate sensation) and
predominantly CN 10 for the efferent limb
(palate elevation).
18.
19. Unilateral palate/larynx dysfunction can be
caused by:
• Brainstem pathology: for example, posterior
inferior cerebellar artery (PICA) stroke causing
lateral medullary syndrome (causing unilateral
palate/laryngeal dysfunction due to involvement
of the nucleus ambiguus;
other symptoms include vertigo, ataxia, Horner’s
syndrome, and/or crossed hemisensory loss
[decreased pain/temperature sensation in the
face ipsilateral to the lesion and body
contralateral to the lesion])
20.
21. Cont…
• Jugular foramen pathology:
for example, glomus jugulare tumor, which
can affect CNs 9, 10, and 11
• Local pathology in the neck: for example,
lymphadenopathy, carotid dissection
• Complication of neck surgery: for example,
thyroid surgery or carotid endarterectomy
22. Cont…
• Isolated unilateral laryngeal dysfunction can
also be caused by pathology in the upper
thorax because the recurrent laryngeal nerve
branch of the vagus nerve descends into the
upper thorax before re-ascending to the larynx
• Therefore, mediastinal, aortic, or apical lung
pathology or cardiothoracic surgery can all
cause recurrent laryngeal nerve dysfunction
leading to hoarseness of the voice.
23.
24. • Bilateral laryngeal/pharyngeal dysfunction is
commonly seen in motor neuron disease (e.g.,
amyotrophic lateral sclerosis [ALS].
25. Glossopharyngeal Neuralgia
• Analogue to trigeminal neuralgia.
• Lancinating neuralgic pain occurs in the throat and/or
ear.
• Pain can be triggered by swallowing.
• Syncope occurs during attacks of glossophayngeal
neuralgia in some cases due to altered visceral afferent
transmission in CN 9.
• Neuroimaging should be obtained to evaluate for the
possibility of compression of CN 9 by a vascular loop
(although most cases are idiopathic), and antiepileptics
such as carbamazepine may be used for treatment.
26. AXIAL 3D CISS IMAGE REVEALS RIGHT GLOSSOPHARYNGEAL NERVE (LARGE ARROWHEAD) IN
CONTACT WITH LOOP FORMED BY RIGHT PICA (ARROWS) AT SUPRAOLIVARY FOSSETTE. ON LEFT
SIDE, NOTE PICA (ARROW) THAT DOES NOT COMPRESS LEFT GLOSSOPHARYNGEAL NERVE (SMALL
ARROWHEAD).
