This presentation summarizes the origin, pathway , testing and clinical implication of cranial nerves 7 to 12

1. Moderated by: Dr. Vidhi Rathi
Presented by: Gauri Bargoti

2. Introduction
Cranial Nerve 0
Cranial Nerve XIV
7th to 12th Cranial Nerve
References

3.  The peripheral nervous system of 12 pairs of cranial nerves emerging from
brain stem.
 Major innervation of the head and neck are supplied by cranial nerves.
 All the cranial nerves are distributed in head and neck except for vagus nerve
that supplies the thorax and abdomen also
 Traditionally 12 pairs of cranial nerves are counted.
 The examination of cranial nerves are an essential part of neurological
examination.

4.  Nervus terminalis (cranial nerve zero) in the adult human
 The plexus appeared in the region of the cribriform plate of the ethmoid and coursed
posteriorly to the vicinity of the olfactory trigone, medial olfactory gyrus, and lamina
terminalis
 The nervus terminalis was identified bilaterally as a microscopic plexus of
unmyelinated peripheral nerve fascicles in the subarachnoid space covering the gyrus
rectus of the orbital surface of the frontal lobes
 References : Fuller GN, Burger PC. Nervus terminalis (cranial nerve zero) in the adult
human. Clinical neuropathology. 1990 Nov 1;9(6):279-83.

5.  Cranial nerve XIV was first identified in 1563, but it was not until 1777 that
it was mentioned in a textbook as the nerve of Wrisberg.
 In modern textbooks, it is referred to as the nervus intermedius or
“intermediary nerve
 Its name is consistent with its intermediary location between the facial nerve
(cranial nerve VII) and the superior section of the vestibulocochlear nerve
(cranial nerve VIII)
 References: Bordoni B, Zanier E. Cranial nerves XIII and XIV: nerves in the shadows.
Journal of multidisciplinary healthcare. 2013;6:87.

6. Facial
nerve
proper
Intermedi
ate nerve(
of
Wrisberg)
Composite of two
nerves:
Somatized efferent fibers for
facial expressions and also
for stapedius, posterior belly
of digastric muscle and
stylohyoid.
It consist of general and
special somatic afferent
fibers and visceral
parasympathetic
efferent fibers

8. Auriculotemporal
nerve joins upper
part of facial nerve
Upper buccal branch
of facial nerve joins
infraorbital branch
in canine fossa
Cervical branch of facial
nerve exchanges fibers
with transverse colli
nerve of cervical plexus

9.  AT THE EXIT FROM STYLOMASTOID FORAMEN
Posterior
auricular-
auricularis
posterior
occipitalis,
intrinsic
muscles on back
of auricle
Digastric
branch-
post
belly of
digastric
Stylohyoid
branch-
stylohyoid

10. Terminal
Branches
1.Temporal Zygomatic Buccal
Marginal
Mandibular
Cervical

12. UPPER MOTOR NEURON INJURY LOWER MOTOR NEURON INJURY
Also called supranuclear Also called infranuclear
Lower part of the face is affected Both upper and lower part of the face is
effected.
Any other sensation not effected Hyperacusis may happen
Effect the upper part of face Do not effect upper face

14. Affected side lost its expression
Nasolabial fold is less pronounced
Furrows of the brow are smoothed out
Eye is more widely open than normal side
Mouth drools to the effected side
Absence of wrinkles

15.  Involve all the facial muscles or only a group of them.
 They occur as a result of aberrant regeneration of facial nerve fibers during
partial recovery from infranuclear lesion.

16.  By asking the patient to close the eyes
 Bell’s phenomenon
 Whistling and smiling test
 Inflation of mouth
 Taste sensation test

17.  Ageusia or loss of taste due to lesion in peripheral or central pathway.
 Test of it is done by using strong solution of sugar and common salt and
weak solution of citric acid and quinine.

18.  Have two parts :
a) Cochlear
b) Vestibular
• Cochlear part is more caudal and dorsal
• Vestibular part is more superior and anterior

20.  Tinnitus
 Hyperacusis
 Recruitment
 Auditory hallucination and delusion of voices
 Vertigo

23.  Arises in an elongated nucleus in 4th ventricle.
 They emerge by several roots along the lateral aspect of the medulla,
beginning rostrally in groove between olive and restiform bodies.

26.  Taste sensation to posterior third of tongue

27.  Rarely damaged alone.
Loss of taste
sensation in
posterior tongue Tickle test to
identify the
abnormality

28.  Largest parasympathetic cranial nerve.
 Contains visceral and somatic fibers.
 It sends somatized fibers to musculature of pharynx and larynx

30.  In jugular foramen:
a) Meningeal
b) Auricular
c) Communicating branches
to glossopharyngeal &
cranial root of accessory
nerve.
Branches arising in the neck:
a) Pharyngeal
b) Carotid
c) Superior laryngeal
d) Right recurrent laryngeal
e) Cardiac

32.  Damage to vagus nerve can be checked only through palatine and laryngeal
branches.

33.  In total paralysis of soft palate: Regurgitation of fluids
 Inability to pronounce words that require palatal closure.
 Dysphagia

34. Direct
visualization
Observing the
movement
with AH!

35.  Unilateral damage is symptom less
 Bilateral damage cause vocal cords to be relaxed.

36. Oculo-Cardiac
Reflex

37. Spinal
part
Cranial
part
Accessory
nerve
Indistinguishable
from VAGUS
NERVE

39.  It innervates laryngeal and pharyngeal muscles
 Gives supply to trapezius and sternocleidomastoid muscle.

40.  TRAPEZIUS: Ask the patient to shrug the shoulder while examiner push them
downwards
 STERNOMASTOID: Weakness of rotation of chin towards opposite side.

41.  Have nucleus in lower part of the floor of 4th ventricle.
 It emerges between anterior pyramid and olive

43. Branches of Hypoglossal nerve
containing fibers of C1:
i. Meningeal branch
ii. Descendens hypoglossi
iii. Branches given to
thyrohyoid & geniohyoid.
Branches arising from Hypoglossal
nerve proper:
Supply all muscles of
tongue except
Palatoglossus.

45.  It supplies tongue and depressors of hyoid.
 Disturbance in nerve may cause:
 Tremor
 Fasciculation of tongue
 Amyotrohic lateral sclerosis

47.  Sicher’s & DuBrul’s oral anatomy-8th ed
 Huthcison’s clinical methods – Swash, M
 Anatomy for surgeons – W. Henry Hollinshead