This lecture was prepared for second year MBBS students of Sir Salimullah Medical College, Dhaka. Here six cranial nerves are described in short and other six are described in detail. You are requested to see the youtube videos for understanding course of the cranial nerves. The lecture was delivered by Dr. Zobayer Mahmud Khan, lecturer, Departmenyt of Anatomy, SSMC.

1. Cranial nerves
Dr. Zobayer Mahmud Khan

2. Number Name Component Function Opening in skull
I Olfactory
Sensory
(SVA)
Smell
Cribriform plate of
the ethmoid bone
Olfactory in
a nut shell
Carry the
special sense
Carry the special sense from
the branchial derivatives
Carry the sense
to the CNS

3. Number Name Component Function Opening in skull
II Optic
Sensory
(SSA)
Vision Optic canal
Optic in a
nut shell
Carry the
special sense
Carry the special sense from
the ectodermal derivatives
Carry the sense
to the CNS

4. No Name Component Function
Opening in
skull
IV Trochlear Motor (GSE)
Assists in turning
the eye downward
and laterally.
Superior
orbital
fissure
Trochlear in
a nut shell
Nucleus Position of Nucleus
Trochlear nucleus Midbrain, at the level of the
inferior colliculus.
It is the only nerve to leave posterior surface of brainstem

5. No Name Component Function
Opening in
skull
III
Occulo-
motor
Motor
(GSE, GVE)
Raised upper eyelid
Turns eyeball upward,
downward & medially
Constrict pupil
Accommodates eye
Superior
orbital
fissure
Occulomotor
in a nut shell
Nucleus Position of Nucleus
Main motor
Accessory parasympathetic
(Edinger-Westphal nucleus)
Midbrain, at the level of the
superior colliculus.

6. No Name Component Function
Opening in
skull
VIII
Vestibulo-
cochlear
Sensory
(SSA)
Utricle and saccule
and semicircular
canals- position and
movement of head
Organ of corti- hearing
Internal
acoustic
meatus
Vestibulocochlear
in a nut shell
Nucleus Position of Nucleus
Cochlear nuclei
Vestibular nuclei
Junction of medulla and pons

7. No Name Component Function
Opening in
skull
VI Abducent Motor (GSE)
Lateral rectus
muscle turns
eyeball laterally
Superior
orbital
fissure
Abducent in
a nut shell
Nucleus Position of Nucleus
Nucleus of Abducent nerve Lower pons, beneath the
colliculus facialis.

10. Comprises three branches
(ophthalmic, maxillary, mandibular).
Two of which are purely sensory and
third is mixed nerve.
Nerve of first brachial arch.

11. Trigeminal nerve nuclei
Main Sensory Nucleus
Spinal Nucleus
Mesencephalic Nucleus
Motor Nucleus

14. Sensory components of the Trigeminal
nerve
Trigeminal
Ganglion
Pain
Temperatur
e
Touch
Pressure
Proprioception
Thalamus
Cerebral
cortex

15. Sensory components of the
Trigeminal nerve

16. General
somatic
afferent
Cornea, skin of forehead, scalp, eyelids,
and nose; also mucous membrane of
paranasal sinuses and nasal cavity
Skin of face over maxilla; teeth of
upper jaw; mucous membrane of
nose, the maxillary sinus, and palate
Skin of cheek, skin over mandible and
side of head, teeth of lower jaw and
Temporomandibular joint; mucous
membrane of mouth and anterior
part of tongue
Functional components

17. General
visceral
efferent
Muscles of mastication, mylohyoid,
anterior belly of digastric, tensor veli
palatini, and tensor tympani
Functional components

18. Distribution of 3 branches of
Trigeminal nerve

20. Nerve of which branchial arch?
Second branchial arch

21. Nucleus of facial nerve
Motor nucleus or branchiomotor
Superior salivatory nucleus or parasympathetic
Lacrimatory nucleus is also parasympathetic
Nucleus of the tractus solitarius which is gustatory
and also receives afferent fibres from the glands

22. Location of the nucleus & roots of facial
nerve
Lower pons
Attached to the brainstem by
two roots, motor and sensory.
The sensory root is also called
the nervus intermedius.

23. Functional component and
distribution
Special visceral or branchial efferent (SVE)
to muscles responsible for facial expression
and for elevation of the hyoid bone

24. General visceral efferent
These fibres are secretomotor to the
submandibular and sublingual salivary
glands, the lacrimal gland, and glands of
the nose, the palate and the pharynx.
General visceral afferent
carries afferent impulses from the
above-mentioned glands.
Functional component and
distribution

25. Special visceral afferent
fibres carry taste sensations from the
palate and from anterior two-thirds of
the tongue except from vallate papillae.
Functional component and
distribution

26. Branches of the Facial nerve
Within the facial canal
Greater petrosal nerve
The nerve to the
stapedius
The chorda tympani
At its exit from the
stylomastoid foramen
Posterior auricular
Digastric
Stylohyoid
Terminal branches within
the parotid gland
Temporal
Zygomatic
Buccal
Marginal mandibular
Cervical
Communicating branches with
adjacent cranial & spinal nerves
Greater petrosal nerve

27. Branches of the Facial nerve

28. No Name Component Function Opening in skull
VII Facial Motor
(SVE)
Muscles of face and
scalp, stapedius
muscle, posterior
belly of digastric
and stylohyoid
muscles
Internal
acoustic
meatus
Facial nerve
in a nut shell

29. No Name Component Function Opening in skull
VII Facial Sensory
(SVA)
Taste from anterior
two-thirds of
tongue, from floor
of mouth and
palate
Internal
acoustic
meatus
Facial nerve
in a nut shell

30. No Name Component Function Opening in skull
VII Facial Secretomotor
(GVE)
Parasympathetic
Submandibular
and sublingual
salivary glands,
lacrimal gland,
and glands
of nose and
palate
Internal
acoustic
meatus
Facial nerve
in a nut shell

32. It is the nerve of the third branchial arch.
Nerve of which branchial arch?

33. Nucleus ambiguous
Inferior salivatory nucleus
Nucleus of the solitary tract
Spinal Nucleus of trigeminal nerve
Nucleus of glossopharyngeal
nerve

34. Nucleus of glossopharyngeal
nerve

35. Special visceral efferent fibres arise in nucleus
ambiguus and supply the stylopharyngeus muscle.
Functional components
General visceral efferent fibres (preganglionic)
arise in inferior salivatory nucleus and travel to
the otic ganglion. Postganglionic fibres arising
in the ganglion to supply the parotid gland

36. Distribution of glossopharyngeal
nerve

37. General visceral afferent fibres are peripheral
processes of cells in inferior ganglion of the
nerve. They carry general sensations from the
pharynx, carotid body and carotid sinus to the
ganglion. The central processes convey these
sensations to the nucleus of the solitary tract.
Functional components

38. Distribution of glossopharyngeal
nerve

39. Special visceral afferent fibres are also
peripheral processes of cells in the inferior
ganglion. They carry sensations of taste from
the posterior one-third of the tongue including
circumvallate papillae to the ganglion. The
central processes convey these sensations to
the nucleus of the solitary tract.
Functional components

40. Distribution of glossopharyngeal
nerve

41. General somatic afferent carry general
sensations (pain, touch, temperature) from
posterior one-third of tongue and tonsil. The
central processes carry these sensations to
nucleus of spinal tract of trigeminal nerve.
Functional components &
Distribution

42. Distribution of glossopharyngeal
nerve

43. Tympanic nerve
Carotid branch
Pharyngeal branches
Muscular branch
Tonsillar branches
Lingual branches
Branches of glossopharyngeal nerve

44. No Name Component Function Opening
in skull
IX Glossopharyngeal Motor
(SVE)
Secreto-
motor
(GVE)
Stylopharyngeus
Muscle
Parotid salivary
gland
Jugular
foramen
Glossopharyngeal
in a nut shell

45. No Name Component Function Opening
in skull
IX Glossopharyngeal Sensory
(GVA,
SVA, GSA)
General sensation
and taste from
posterior one-
third of tongue
and pharynx;
carotid Sinus
(baroreceptor);
and carotid body
(chemoreceptor)
Jugular
foramen
Glossopharyngeal
in a nut shell

47. Extensive (‘vague’) course, through the head,
the neck, the thorax and the abdomen.
The fibers of the cranial root of the accessory
nerve are also distributed through it.
The vagus nerve bears two ganglia,
superior and inferior.

49. Nucleus ambiguus (branchiomotor)
Dorsal nucleus of vagus (parasympathetic)
Nucleus of tractus solitarius (gustatory)
Spinal Nucleus of trigeminal nerve
Nucleus of vagus nerve

50. Special visceral efferent fibres arise in the
nucleus ambiguus and supply the muscles
of the palate, pharynx and larynx.
General visceral efferent fibres arise in the
dorsal motor nucleus of the vagus. These
are preganglionic parasympathetic fibres.
They are distributed to thoracic and
abdominal viscera. The postganglionic
neurons are situated in ganglia lying close
to (or within) the viscera to be supplied.
Functional components &
Distribution

51. Distribution of the vagus nerve

52. General visceral afferent fibres are peripheral
processes of cells located in the inferior ganglion of
the nerve. They bring sensations from the pharynx,
larynx, trachea, oesophagus and from the abdominal
and thoracic viscera. These are conveyed by the
central processes of the ganglion cells to the nucleus
of the tractus solitarius. Some of these fibres
terminate in the dorsal nucleus of the vagus.
Functional components &
Distribution

53. Distribution of the vagus nerve

54. Special visceral afferent fibres are also peripheral
processes of neurons in the inferior ganglion. They
carry sensations of taste from the posterior most part
of the tongue and from the epiglottis. The central
processes of the cells concerned terminate in the
lower part of the nucleus of the tractus solitarius.
Functional components &
Distribution

55. Distribution of the vagus nerve

56. General somatic afferent fibres are peripheral
processes of neurons in the superior ganglion and are
distributed to the skin of the external ear. The central
processes of the ganglion cells terminate in relation
to the spinal nucleus of the trigeminal nerve.
Functional components &
Distribution

57. Distribution of the vagus nerve

58. In the jugular foramen,
the superior ganglion gives off-
Meningeal, and
Auricular branches
The ganglion also gives off communicating
branches to the glossopharyngeal and
cranial root of accessory nerves and to the
superior cervical sympathetic ganglion.
Branches of vagus nerve

59. Branches arising in the neck are as follows-
Pharyngeal branch
Carotid branches
Superior laryngeal nerve
External laryngeal nerve
Internal laryngeal nerve
Right recurrent laryngeal
Left recurrent laryngeal nerve
Cardiac branches
Branches of vagus nerve

60. Branches of vagus nerve

61. Distribution of the vagus nerve

62. No Name Component Function
Opening in
skull
X Vagus Motor
(GVE, SVE)
Sensory
(GVA, SVA,
GSA)
Heart and great thoracic
blood vessels; larynx,
trachea, bronchi & lungs;
alimentary tract from
pharynx to splenic
flexure of colon, liver,
kidneys, and Pancreas
Jugular
foramen
Vagus in a
nut shell

64. Entirely motor in function having two roots
Cranial root and Spinal root.
Cranial root is accessory to the vagus, and is
distributed through the branches of the latter.
Spinal root has a more independent course.

65. Formation of accessory nerve

66. Special visceral (branchial) efferent
from the lower part of nucleus
ambiguus. It is distributed through
the branches of vagus to the muscles
of the palate, the pharynx, the larynx.
Functional components &
Distribution

67. Special visceral efferent from a long spinal
nucleus situated in the lateral part of the
anterior grey column of the spinal cord
extending between segments C1 to C5. Its
fibres supply the sternocleidomastoid and
the trapezius muscles.
Functional components &
Distribution

68. Cranial root - nucleus ambiguus
Efferent fibers –
olive & inferior cerebellar peduncle
Runs laterally – joins spinal root
Leave the skull through the jugular foramen
Roots then separate &
cranial root joins the vagus nerve
Corticonuclear
fibers
Distributed in its pharyngeal and recurrent
laryngeal branches to the muscles of the
soft palate, pharynx, and larynx

69. Spinal root - spinal nucleus of
upper five cervical segments
Efferent fibers – between the
anterior & posterior nerve roots
of the cervical spinal nerves
Form a nerve trunk that ascends
through the foramen magnum
Spinal root passes laterally and
joins the cranial root
Corticonuclear
fibers
Spinal root separates from the cranial
root & enters the deep surface of the
sternocleidomastoid muscle
Crosses the
posterior triangle
of the neck &
passes beneath
trapezius muscle

70. Distribution of accessory nerve

71. No Name Component Function
Opening in
skull
XI Accessory
Cranial
root
Motor
(SVE)
Muscles of soft palate
(except tensor veli
palatini), pharynx
(except stylopharyngeus)
and larynx
(except cricothyroid)
Jugular
foramen
Accessory in
a nut shell

72. No Name Component Function
Opening in
skull
XI Accessory
Spinal
root
Motor
(SVE)
Sternocleidomastoid
and trapezius
muscles
Jugular
foramen
Accessory in
a nut shell

74. The hypoglossal nerve is entirely
motorin function
The hypoglossal nerve supplies the intrinsic
muscles of the tongue and the styloglossus,
hyoglossus, and genioglossus muscles.

75. Anterolateral sulcus of the medulla,
between the pyramid and the olive,
by 10 to 15 rootlets.
Hypoglossal nerve attachment

77. General somatic efferent arise from
hypoglossal nucleus which lies in the
medulla, in the floor of fourth ventricle
deep to the hypoglossal triangle
supplies the muscles of the tongue.
Functional components &
Distribution

78. Greater part of the hypoglossal
nucleus receives corticonuclear fibers
from both cerebral hemispheres.
nerve fibers responsible for supplying
the genioglossusmuscle only
receive corticonuclear fibers from the
opposite cerebral hemisphere
But

79. No Name Component Function Opening in skull
XII
Hypoglossal Motor
(GSE)
Muscles of tongue
(except
palatoglossus)
controlling its
shape and
movement
Hypoglossal
canal
Hypoglossal
in a nut shell

80. • Anosmia
• Ophthalmoplegia
• Strabismus
• Trigeminal Neuralgia
• Bell’s Palsy
• Vertigo nystagmus
• Deafness and tinnitus
• Pharyngeal or gag reflex
• Drooping of the shoulder and inability
to turn the chin to opposite side
• Tongue lesion

82. , '

83. Distribution of cranial nerves

84. Distribution of cranial nerves