CRANIAL NERVES

1. CRANIAL NERVES

2. Referred by name, number or both • Can be motor, sensory, or both • Number represents inverse height in the brainstem • Cranial nerves 1-5 are found at the level of the midbrain • Cranial nerves 5-7 are pons-level • Cranial nerves 9-12 are found in the medulla • P. 583 for illustration CRANIAL NERVE CLASSIFICATION

3. Sensory only • Mediates the sense of smell • Sensors are in the epithelium of the nasal cavity • Divides into medial and lateral branches • Damage includes loss of sense of smell CRANIAL NERVE IOLFACTORY

4. Sensory only • Spatial discrimination • Form analysis • Responses to light • Interaction between visual and auditory information • Damage can result in • Varying losses of vision in one eye • Visual field cut • Visual Tracking deficits Cranial Nerve IIOptic Nerve

5. Motor only • It serves the muscles responsible for adducting the eye, elevating the eyelid, and pupil constriction • Passes near the circle of Willis • Works with IV and VI • Damage affects • Abduction of the eye and inability to turn the eye in • Drooping of the eyelid • Abnormal dilation of the pupil CRANIAL NERVE IIIOculomotor Nerve

6. Motor only • Arises from the trochlear nucleus of the midbrain • Innervates the superior oblique muscle of the eye • Turns the eye down and slightly out • Used for visual tracking • Damage includes double vision when looking down/out CRANIAL NERVE IVTrochlear Nerve

7. Motor and Sensory • Provides motor supply to the muscles of mastication • Transmits sensory information from the face • Largest • Divides into three components • Opthalmic Nerve • Maxillary Nerve • Mandibular Nerve CRANIAL NERVE VTRIGEMINAL NERVE

8. Transmits sensory information from the face, mouth, and mandible • Transmits info about all kinds of sensation, except taste, from the anterior 2/3 of the tongue CRANIAL NERVE VTRIGEMINAL NERVE

9. Innervates Masseter- Elevates and closes the mandible • Innervates Temporalis- Elevates, Retracts and assists inclosing the mandible • Innervates medial and lateral pterygoid-depresses, opens, lateralizes, and protrudes the mandible • Innervates Tensor Veli Palatini- tenses the velum CRANIAL NERVE VTRIGEMINAL NERVE

10. Damage includes: • Decreased jaw movement • Decreased face, mouth and jaw sensation • Decreased mastication • Decreased oral containment • Bilateral nerve damage includes: Severely decreased articulatory precision CRANIAL NERVE VTRIGEMINAL NERVE

11. Motor Nerve • Lateral Eye movement • Damage may include double vision and eye pulling to nasal side Cranial Nerve VIAbducens Nerve

12. Motor and Sensory Nerve • P. 605 for illustration • Innervates obicularisoris for mastication • Innervates zygomaticus for mastication • Innervates buccinator for oral control • Provides taste to the anterior 2/3 of tongue CRANIAL NERVE VIIFACIAL NERVE

13. Sensory only • Known as the auditory nerve • Mediates both hearing and balance • Damage may include: facial pain/numbness, headache, tinnitus • Damage includes: • Ipsilateral (on the same side) hearing loss • Disturbances of equilibrium arising from the loss of information concerning position in space CRANIAL NERVE VIIIVestibulocochlear Nerve

14. Motor and Sensory Nerve • Mediates taste to the posterior one-third of the tongue, portion of the soft palate • Provides sensation of touch, pain and temperature from the posterior one-third of the tongue, faucialpilars, upper pharynx and Eustachian tube • Innervates stylopharyngeus muscle which elevates the larynx and pulls it forward during the pharyngeal stage of the swallow • Innervates mucous membrane of middle ear and Eustachian tube CRANIAL NERVE IXGlossopharyngeal Nerve

15. Damage may include: • Difficulty initiating swallow • Loss of taste/sensation for back 1/3 of tongue • Unilateral loss of gag reflex • Damage may include: • Deviation of uvula • Tachycardia CRANIAL NERVE IXGlossopharyngeal Nerve

16. Motor and Sensory • Courses through neck and thorax: extends into abdomen • Branches- Superior Laryngeal Nerve, Recurrent Laryngeal Nerve • Transmits sensory info from skin covering ear drum, posterior auricle, and external auditory meatus • Transmits sensory info from lower pharynx, larynx, thoracic and abdominal viscera, esophagus and bronchi CRANIAL NERVE XVagus Nerve

17. Recurrent Laryngeal Nerve transmits sensory information below the vocal folds and from the tympanic membrane and external auditory meatus. • Pharyngeal Branch mediates sensation from base of tongue, velum, posterior and inferior portions of the pharynx and larynx CRANIAL NERVE XVagus Nerve

18. Superior Laryngeal Nerve receives information from laryngeal region above the vocal folds and cricothyroid muscle • Sensory and motor response to silent laryngeal penetration • Damage may include: • Aspiration during or after the swallow, inability to cough, residue in valleculae • Hypernasality, breathy vocal quality, hoarseness, reduced pitch range, reduced volume CRANIAL NERVE XVagus Nerve

19. Motor only • Works with the vagus to innervate the intrinsic muscles of the larynx, pharynx, and soft palate • Serves both the recurrent laryngeal and pharyngeal nerves of the vagus • Works to depress velum (shortens) • Innervates voluntary muscles of the soft palate, pharynx, and larynx for swallowing • Damage includes inability to turn head, shrug shoulders, raise arms, voice problems CRANIAL NERVE XIAccessory Nerve

20. Motor Only • Innervates all intrinsic muscles of the tongue • Innervates all extrinsic muscles of the tongue except the palatoglossus • Important for tongue movements for swallowing and speech • Damage may include: • Reduced bolus control • Reduced anterior to posterior movement • Articulation errors CRANIAL NERVE XIIHypoglosssal Nerve