18.-Cranial-Nerves-to-send.ppt - Cranial Nerves Cranial...

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Unformatted text preview: Cranial Nerves Cranial Nerves • 12 pairs, (two are attached to the cerebrum and 10 are attached to the brain stem • Nine are attached to the ventral surface of the brain stem, while one is attached to the back of the midbrain (Trochlear). Cranial Nerves Like all nerves, cranial nerves are made up of bundles of axons Cranial nerves may be sensory, or motor, or mixed, and may contain somatic and/or autonomic fibers. Review… bones Review… bones Foramina of Exit NERVE FORAMEN NERVE FORAMEN 1st Cribriform plate of ethmoid 7th Internal acoustic meatus, 2nd Optic canal 8th 3rd 4th 5th(V1) stylomastoid foramen Internal acoustic meatus 9th Superior orbital fissure 10th 6th 5th(V2) Foramen rotundum 11th 5th(V3) 12th Foramen ovale Jugular foramen Hypoglossal canal Numbers & Names Facial Vestibulocochlear I Olfactory VII II Optic VIII III Occulomotor IX Glossopharyngeal IV Trochlear X Vagus V Trigeminal XI Accessory • Cranial part • Spinal part Abducent XII Hypoglossal V1: Ophthalmic V2: Maxillary V3: Mandibular VI (Statoacoustic) Cranial Nerves Special Sense Nerves I,II,VIII Somatic Motor Nerves Eye—III,IV,VI Tongue--XII “Rest of body” nerves IX,X,XI Face and jaws VII, V Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves Nerve “targets” in head 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 MOTOR Muscles Glands eyes salivary extrinsic sweat intrinsic lacrimal jaws mucous facial expression larynx tongue throat ear Head I: Skull—a framework to hang on Overall organization of skull Base of the skull—the hard part 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 Base of the skull—cranial nerves out 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 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 EXIT CR. CAVITY IV. Trochlear Superior oblique m. (with trochlea) Lateral rectus •Sup.,med.,inf.rectus • Inferior Oblique •Levator palpebrae superioris Intrinsic, extrinsic mm. of tongue Sup. Orbital fissure (sphenoid) “ “ VI. Abducens III. Oculomotor (Also parasympathetic to ciliary mm, constrictor pupillae) XII. Hypoglossal Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves 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 Human Anatomy, Frolich, Head/Neck IV: Cranial Nerves VII: Facial Nerve (exits cranial cavity with VIII--internal auditory meatus) Facial muscles (five branches fan out over face from stylomastoid foramen) “chorda tympani” (crosses interior ear drum to join V3 ) 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!) V1. Ophthalmic V2. Maxillary 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 V3. Mandibular 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 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 .htm Mnemonic On Old Olympus’ Tower Top A Fin And German Viewed A Hop MNEMONIC OLFACTORY OPTIC OCULOMOTOR TROCHLEAR TRIGEMINAL ABDUCENS FACIAL VESTIBULOCOCHLEAR GLOSSOPHARYNGEAL VAGUS ACCESSORY HYPOGLOSSAL OH ONCE ONE TAKES THE ANATOMY FINAL VERY GOOD VACATION A-HEAD CN I: OLFACTORY Cranial nerve I Function: smell Clinical test for damage: determine whether a person can smell something aromatic CN II: OPTIC Cranial nerve II Function: Clinical test for damage: vision tests peripheral vision and visual acuity Effects of damage: blindness in part or all of the visual field 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 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 CN V: TRIGEMINAL Cranial nerve V Function: sensory nerve of the face Clinical test for injury: corneal reflex; sense of touch, pain, and temperature; clench teeth; move mandible side to side Effects of damage: loss of sensation and impaired chewing CN VI: ABDUCENS 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 CN VII: FACIAL 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 Bell’s Palsy • Damage to facial nerve results in paralysis of facial muscles: Facial (Bell’s palsy);lower motor neuron lesion (whole face affected) • NB. In upper motor neuron lesion (upper face is intact) . Face is distorted: drooping of lower eyelid, sagging of the angle of the mouth, dribbling of saliva, loss of facial expressions, loss of chewing, blowing, sucking, unable to show teeth or close the eye on affected side CN VIII: VESTIBULOCOCHLEAR 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 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 CN X: VAGUS 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 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 CN XII: HYPOGLOSSAL 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 Lesion of Cranial Nerves Causes: Severe head injuries, skull bone fractures or penetrating wounds Brain lesions Compression due to raised intracranial pressure (due to any space occupying lesion e.g. tumor, hematoma, or CSF obstruction ) Cavernous sinus thrombosis Cavernous Sinus Thrombosis Clinical tests for Cranial Nerves • The integrity of nerves is assessed by examining the: – The sensations in the area of distribution – Action of muscles – Integrity of reflexes – Secretory activity of glands Reflexes Related to Cranial Nerves • • • • • • • Pupillary (light) Accommodation Corneal (Blinking) Lacrimation Salivation Sneezing Vomiting CN _, _ CN _, _ CN _,_ CN _, _ CN _, _, _, _, _ CN _, _, _, _, _ CN _, _, _, _ Reflexes Related to Cranial Nerves • Yawning • Swallowing • Jaw jerk • Stapedial • Cough • Gag CN _, _ CN _, _, _, _, _ ,_ CN _ CN _, _ CN _, _, _, CN _ ,_ Clinical Tests for Cranial Nerves Olfactory nerve: Ask the patient to identify items with very specific odors,(e.g.. coffee, alcohol, perfume), placed under the nose. Each nostril is tested separately Optic nerve: Ask the patient to read an eye chart. – Peripheral vision is tested by detecting object or movement from corners of the eyes Occulomotor nerve: Note the ability to move each eye upward, downward and inward by asking the person to follow a target moved by the examiner. – Also examine the constriction of pupil & accommodation Clinical Tests for Cranial Nerves • Trochlear: – Note the ability to move each eye downward and inward • Trigeminal nerve: – General sensations on face are tested by using a pin and a wisp of cotton. – Blink reflex is tested by touching the cornea of the eye with a cotton wisp. – Strength and action of muscles of mastication are tested by asking the person to clench the teeth and open the jaw against resistance • Abducent nerve: – Note the ability to move each eye outward beyond the midline Clinical Tests for Cranial Nerves • Facial nerve: – The action of muscles of face is tested by asking the person to smile, to open the mouth, to show the teeth, and to close the eyes tightly. – Taste sensations from anterior 2/3 tongue is tested using substances that are sweet, sour, salty and bitter • Vestibulocochlear nerve: – Hearing is tested with a tuning fork. – Balance is tested by asking the person to walk on a straight line. Clinical Tests for Cranial Nerves • Glossopharyngeal & Vagus nerves: • (cranial part of Accessory nerve) : – The person is asked to swallow. – The person is asked to say ‘ah-h-h’ to check the movements of palate and uvula. – The ‘gag reflex’ is tested by touching the back of the throat by the tongue depressor. – The person is asked to speak to check the voice for hoarsness. Clinical Tests for Cranial Nerves • Spinal part of Accessory nerve: – The person is asked to turn the head and to shrug the shoulders against resistance provided by the examiner • Hypoglossal nerve: – The person is asked to stick out the tongue, to observe the deviation to one side or the other ...
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