Cranial Nerves Cranial Nerves n Special Sense Nerves

Cranial Nerves

Cranial Nerves n Special Sense Nerves n n I, II, VIII Somatic Motor Nerves Eye—III, IV, VI n. Tongue--XII n n “Rest of body” nerves n n IX, X, XI Face and jaws n VII, V Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

n Head I: Skull—a framework to hang on n n Overall organization of skull Base of the skull—the hard part n n n Developmental view Cranial nerves out (to “targets”) Head II: Throat targets Head III: Special Sense targets Head IV: Cranial nerves in depth Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

Nerve “targets” in head n SENSORY Special Smell Vision Hearing General skin teeth eye tongue oral cavity nasal cavity middle ear throat meninges Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves n MOTOR Muscles Glands eyes salivary extrinsic sweat intrinsic lacrimal jaws mucous facial expression larynx tongue throat ear

Base of the skull—cranial nerves out n n n Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves 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

Cranial nerves

Special Sense Nerves NERVE TARGET EXIT FROM CRANIAL CAVITY I. Olfactory epithelium Cribiform plate (ethmoid) II. Optic Retina Optic canal (sphenoid) VIII. Auditory Inner ear Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves Internal auditory meatus (temporal)

M&M, Table 14. 3 Human Anatomy, Frolich, Head/Neck IV: 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)

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

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

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

Cranial nerves

Cranial nerves

“Rest of body” nerves (all exit from jugular foramen) Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

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

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

VII: Facial Nerve (exits cranial cavity with VIII--internal auditory meatus) n Facial muscles (five branches fan out over face from stylomastoid foramen) n n n “chorda tympani” (crosses interior ear drum to join V 3 ) n n n Temporal Zygomatic Buccal Mandibular Cervical Taste to anterior 2/3 of tongue Submandibular, sublingual salivary glands Lacrimal glands Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

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

V: Trigeminal (3 nerves in 1!) n V 1. Ophthalmic n n n V 2. Maxillary n n n Exits with eye muscle group (superior orbital fissure, through orbit to superior orbital notch/foramina) Sensory to forehead, nasal cavity Exits foramen rotundum through wall of maxillary sinus to inferior orbital foramina) Sensory to cheek, upper lip, teeth, nasal cavity V 3. Mandibular n n Exits foramen ovale to mandibular foramen to mental foramen Motor to jaw muscles--Masseter, temporalis, pterygoids, digastric Sensory to chin Sensory to tongue Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves

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

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

Cranial Nerves n n n I: Olfactory II: Optic III: Oculomotor IV: Trochlear V: Trigeminal VI: Abducens n n VII: Facial VIII: Vestibulocochlear n n n Acoustic IX: Glossopharyngeal X: Vagus XI: Accessory XII: Hypoglossal http: //www. gwc. maricopa. edu/class/bio 201/cn/cranial. htm

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

MNEMONIC n n n OLFACTORY OPTIC OCULOMOTOR TROCHLEAR TRIGEMINAL ABDUCENS FACIAL VESTIBULOCOCHLEAR GLOSSOPHARYNGEAL VAGUS ACCESSORY HYPOGLOSSAL n n n OH ONCE ONE TAKES THE ANATOMY FINAL VERY GOOD VACATION A-HEAD

CN I: OLFACTORY n n Cranial nerve I Function: n n smell Clinical test for damage: n determine whether a person can smell something aromatic

CN II: OPTIC n n Cranial nerve II Function: n n Clinical test for damage: n n vision tests peripheral vision and visual acuity Effects of damage: n blindness in part or all of the visual field

CNIII: OCULOMOTOR n n Cranial nerve III Function: n eye movements, opening of eyelid, constriction of pupil, focusing, proprioception Clinical tests for injury: n differences in pupil size; pupillary response to light; eye tracking Effects of damage n dropping eyelid, dilated pupil, double vision

CNIV: TROCHLEAR n n 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

CN V: TRIGEMINAL n n Cranial nerve V Function: sensory nerve of the face Clinical test for injury: n corneal reflex; sense of touch, pain, and temperature; clench teeth; move mandible side to side Effects of damage: n loss of sensation and impaired chewing

CN VI: ABDUCENS AND CN VII: FACIAL n n 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 n n 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

CN VIII: VESTIBULOCOCHLEAR n n Cranial Nerve VIII Function: hearing and equilibrium Clinical tests: test hearing, balance, and ability to walk a straight line Effects of damage: deafness, dizziness, nausea, loss of balance, and nystagmus

CN IX: GLOSSOPHARANGEAL AND CN X: VAGUS n n Cranial Nerve IX Function: swallowing, salivation, gagging; touch, pressure, taste, and pain sensations from tongue, pharynx, and outer ear Clinical tests: gag reflex, swallowing, and coughing Effects of damage: difficulty swallowing n n Cranial Nerve X Function: swallowing; taste; speech; respiratory, CV, and GI regulation; sensations of hunger, fullness, and intestinal discomfort Clinical tests: test with cranial nerve IX Effects of damage: hoarseness or loss of voice; impaired swallowing and GI motility

CN XI: ACCESSORY AND CN XII: HYPOGLOSSAL n n 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 n n 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