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) Oculomotor (III) Trochlear (IV) Trigeminal (V) Abducens (VI) Facial (VII)

Vestibulocochlear (VIII) Also known as auditory

Glossopharyngeal (IX) Vagus (X) Accessory (XI)

Also known as spinal accessory

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

Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

Base of the skull—cranial nerves out Ethmoid (olfactory)

I. Olfactory Sphenoid (optic)

II. OpticIII. OculomotorIV. TrochlearVI. Abducens

Temporal (otic)VII. Acoustic/Auditory/

Vestibulocochlear Face/Jaws

V. TrigeminalVII. Facial

Throat (rest of body)IX GlossopharyngealX. VagusXI. Spinal AccessoryXII. Hypoglosal

Cranial nerves

Cranial nerves

Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

Somatic Motor Nerves(eye muscles and tongue)

EXIT CR. CAVITYTARGETNERVE

Hypoglossal canal

(occipital)

Intrinsic, extrinsic mm. of tongue

XII. Hypoglossal

“•Sup.,med.,inf.rectus• Inferior Oblique•Levator palpebrae superioris

III. Oculomotor(Also parasympathetic to ciliary mm, constrictor pupillae)

“Lateral rectusVI. Abducens

Sup. Orbital fissure (sphenoid)

Superior oblique m. (with trochlea)

IV. Trochlear

Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

“Rest of body” nerves(all exit from jugular foramen)

NERVE TARGET

X: Vagus Somatic motor to larynx/pharynx Parasympathetic to most of gut Taste to back posterior pharynx

XI: (Spinal) Accesory

Motor to traps, sternocleidomastoid

IX: Glosso-pharyngeal

Sensory to carotid body/sinus Taste to posterior tongue Sensory to ear opening/middle

ear Parotid salivary gland

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 Function: Eye movements Clinical test: lateral eye

movement Effects of damage:

inability to rotate eye laterally; at rest – eye rotates medially because of action of antagonistic muscles

Cranial Nerve VII Function: facial

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

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 Function: swallowing; head,

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

Cranial Nerve XII Function: tongue movements

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: Olfactory II: Optic III: Oculomotor IV: Trochlear V: Trigeminal VI: 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 Old Olympus’ Tower Top A

Fin And German Viewed A Hop