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. 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

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)

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

Mnemonic On Old Olympus’ Tower Top A Fin And German Viewed A Hop