Motor
cranial
nerves
 Cranial nerves are part of the peripheral
nervous system.
 Carry sensory or motor information or a
combination and function in parasympathetic
nervous system.
 Cranial nerves I, II and VIII are purely
sensory.
 Cranial nerves III, IV, VI, XI and XII are motor
(although also function balance).
Cranial Nerves
 Indicated by Roman
numerals I-XII from anterior
to posterior
 May have one or more of 3
functions



Sensory (special or
general)
Motor (skeletal
muscles)
Parasympathetic
(regulation of glands,
smooth muscles,
cardiac muscle)
 Balance

Positional information
of body parts
Cranial Nerves
 Olfactory (I)
 Optic (II)
 Vestibulocochlear (VIII)
 Also known as auditory
 Oculomotor (III)
 Glossopharyngeal (IX)
 Trochlear (IV)
 Vagus (X)
 Trigeminal (V)
 Accessory (XI)
 Also known as spinal
accessory
 Abducens (VI)
 Facial (VII)
 Hypoglossal (XII)
Mnemonic Aids for Cranial
Nerves
• To remember at least part of the sequence of the first set of
cranial nerves that begin with the letter O, try this –
You have I nose. You have II eyes.
I - Olfactory; II -- Optic
Mnemonic Aids for Cranial
Nerves
• On Old Olympus Towering Tops A Famous Vocal German
Viewed Some Hops
• Olfactory, Optic, Oculomotor, Trochlear, Trigeminal,
Abducens, Facial, Vestibulocochlear, Glossopharyngeal, Vagus,
Spinal Accessory (Accessory), Hypoglossal
• Oh. Oh. Ooh...To Touch And Feel Very Green Vegetables...A
H !!!
• Oh, once one takes the anatomy final- very good vacations
are heavenly!
Motor cranial nerves
 Cranial nerve IV Trochlear
 Cranial nerve VI Abducens
 Cranial nerve XI Accessory
 Cranial nerve XII Hypoglossal
Base of the skull—cranial nerves out
 Ethmoid (olfactory)




Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
I. Olfactory
Sphenoid (optic)
II. Optic
III. Oculomotor
IV. Trochlear
VI. Abducens
Temporal (otic)
VII. Acoustic/Auditory/
Vestibulocochlear
Face/Jaws
V. Trigeminal
VII. Facial
Throat (rest of body)
IX Glossopharyngeal
X. Vagus
XI. Spinal Accessory
XII. Hypoglosal
Cranial nerves
Cranial nerves
Somatic Motor Nerves
(eye muscles and tongue)
NERVE
TARGET
IV. Trochlear
Superior oblique m.
(with trochlea)
VI. Abducens
Lateral rectus
III. Oculomotor
•Sup.,med.,inf.rectus
(Also parasympathetic
• Inferior Oblique
to ciliary mm, constrictor
•Levator palpebrae
pupillae)
superioris
XII. Hypoglossal
Intrinsic, extrinsic
mm. of tongue
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
EXIT CR. CAVITY
Sup. Orbital fissure
(sphenoid)
“
“
Hypoglossal canal
(occipital)
“Rest of body” nerves
(all exit from jugular foramen)
NERVE
TARGET
 Somatic motor to larynx/pharynx
 Parasympathetic to most of gut
 Taste to back posterior pharynx
XI: (Spinal)  Motor to traps,
Accesory
sternocleidomastoid
IX: Glosso-  Sensory to carotid body/sinus
pharyngeal  Taste to posterior tongue
 Sensory to ear opening/middle
ear
 Parotid salivary gland
X: Vagus
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Cranial Nerve III Oculomotor
 Motor to four eyeball muscles
 Parasympathetic to ciliary ganglion
 Injury to nerve causes dilated pupil and ptosis
 “fixed and dilated”
Cranial Nerves
 Olfactory (I)
 Sensory (smell)
• Optic (II)
– Sensory (sight)
• Oculomotor (III)
– Motor (4 of 6 eye
muscles)
– Parasympathetic
(constriction of pupil,
movement of lens)
III Occulomotor
 The somatic motor
component of CN III
plays a major role in
controlling the muscles
responsible for the
precise movement of
the eyes for visual
tracking or fixation on
an object.
CNIII: OCULOMOTOR
 Cranial nerve III
 Function:

eye movements, opening of
eyelid, constriction of pupil,
focusing, proprioception
 Clinical tests for injury:

differences in pupil size;
pupillary response to light; eye
tracking
 Effects of damage

dropping eyelid, dilated pupil,
double vision
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Cranial Nerves
 Trochlear (IV)
 Visual tracking of eye
• Trigeminal (V)
– Sensory (face, nasal
cavity, cheeks, lips, skin of
mandible)
–Motor (muscles of
mastication, anterior belly
of digastric, mylohyoid)
• Abducens (VI)
– Motor (1 eye muscle)
IV Trochlear
 The superior oblique
muscle is one of the
six extraocular
muscles responsible
for the precise
movement of the eye
for visual tracking or
fixation on an object.
CNIV: TROCHLEAR
 Cranial nerve IV
 Function: eye movements and
proprioception
 Clinical test for injury: ability to
rotate eye inferolaterally
 Effects of damage – double
vision, patient tilts head toward
affected side
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
VI Abducens
 The lateral rectus
muscle is one of the
six extraocular
muscles responsible
for the precise
movement of the eye
for visual tracking or
fixation on an object.
CN VI: ABDUCENS AND CN
VII: FACIAL
 Cranial Nerve VI
 Cranial Nerve VII
 Function: Eye movements
 Function: facial
 Clinical test: lateral eye
expression; sense of taste
 Clinical test: motor
functions – close eyes,
smile, whistle, frown, raise
eyebrows; taste
 Effects of damage:
inability to control facial
muscles; distorted sense
of taste
movement
 Effects of damage:
inability to rotate eye
laterally; at rest – eye
rotates medially because
of action of antagonistic
muscles
Cranial Nerves
 Vagus (X)



Sensory (taste, back of
mouth, larynx, thoracic and
abdominal organs)
Motor (muscles of larynx, 1
muscle of tongue)
Parasympathetic (thoracic
and abdominal organs)
• Accessory (XI)
– Motor (sternocleidomastoid,
trapezius)
• Hypoglossal (XII)
– Motor (tongue
and throat muscles)
XI Accessory
 Innervates the trapezius
and
sternocleidomastoid
muscles.
 Shrug your shoulders
CN XI: ACCESSORY AND
CN XII: HYPOGLOSSAL
 Cranial Nerve XI
 Cranial Nerve XII
 Function: swallowing; head,
 Function: tongue movements
neck, and shoulder
movements
 Clinical tests: rotate head
and shrug shoulders against
resistance
 Effects of damage: impaired
movement of head, neck,
and shoulders; paralysis of
sternocleidomastoid
of speech, food
manipulation, and
swallowing
 Clinical test: tongue function
 Effects of damage: difficulty
in speech and swallowing;
atrophy of tongue; inability to
stick out (protrude) tongue
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
XII Hypoglossal
 Movement of the
tongue
Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves
Cranial Nerves
 I:
 II:
 III:
 IV:
 V:
 VI:
Olfactory
Optic
Oculomotor
Trochlear
Trigeminal
Abducens
 VII: Facial
 VIII:Vestibulocochlear
 Acoustic
 IX: Glossopharyngeal
 X:
Vagus
 XI: Accessory
 XII: Hypoglossal
http://www.gwc.maricopa.edu/class/bio201/cn/cranial.htm
Mnemonic
 On
 Fin
 Old
 And
 Olympus’
 German
 Tower
 Viewed
 Top
 A
 A
 Hop