Cranial Nerve Flashcards
CN I
- Olfactory nerve
- Function: Sense of smell
CN I test
- Have patient use each nostril separately to smell non-irritating substance (cinnamon, coffee, etc.)
- Often omitted from exam unless frontal lobe damage is suspected or patient says trouble with smell
- Abnormal findings: Anosmia
CN II
- Optic nerve
- Function: Vision (fields, acuity), pupillary reflexes
CN II test
- Visual field testing - confrontation test; issues = hemianopia, quadrantonopia; visual extinction = visual inattention to one side –> tested with inattention test)
- Visual acuity testing - Snellen chart
CN III
- Oculomotor nerve
- Function: Eye movements (medial, superior, inferior rectus & inferior oblique); pupillary construction & accomodation; eyelid opening (levator palpabrae)
CN III test
- EOM - ability to move eyes
- Pupillary reflexes - convergence of pupils, re-activity to light
- Eyelid opening - observation of ptosis
- Possible impairments: diploplia, poorly coordinated movements, paralysis, nystagmus, abnormal resting position, ptosis, loss of accommodation, absent/impaired re-activity to light
CN IV
- Trochlear Nerve
- Function: Eye movement (superior oblique - depression & adduction)
CN IV test
- EOM testing
- Possible Impairments: Diploplia, inability to look down while eye is adducted
CN V
- Trigeminal nerve
- Function: Facial sensation, corneal reflex, jaw movements
CN V test
- Cranial sensation - cotton swab to face & scalp
- Corneal reflex - cotton swab to cornea
- Jaw movements - palpation of temporalis & masseter + strength testing of jaw opening and closure
- Possible impairments: Decreased sensation, numbness, decreased or absent blink, jaw deviation, weakness of chewing
CN VI
- Abducens nerve
- Function: Abduction of eye (lateral rectus)
CN VI test
- EOM testing
- Possible impairment: Diploplia with lateral gaze
CN VII
- Facial nerve
- Function: Sensation and taste to anterior 2/3 tongue; sensation to external part of ear; facial movement; eyelid closure
CN VII test
- Taste - different foods on tongue
- Sensation - cotton swab to ear
- Facial movements - observe symmetry; have patient smile, puff out cheeks, purse lips, wrinkle forehead; raise eyebrows, close eyelids
- Possible impairments: Decreased or absent sensation and taste; Drooping face; Asymmetry of face; Facial weakness or paralysis; Inability to close eyes
CN VIII
- Vestibulocochlear nerve
- Function: Cochlear-hearing; vestibular-equilibrium (VOR); gaze fixation
CN VIII test
- Auditory - tuning fork, rubbing fingers together, watch
- Vestibular - gaze fixation, balance, analysis of dizziness
- Possible impairments: Diminished/absent hearing or tinnitus; Vertigo; Disequilibrium; Nystagmus; Poor gaze stability with head movements; Positional vertigo and nystagmus
CN IX
- Glossopharyngeal Nerve
- Function: Taste & sensation to posterior 1/3 tongue; sensation to pharynx, middle & external ear; elevation of pharynx; parotid gland secretory fibers
CN IX test
- Gag reflex - stimulation of pharyngeal wall - look for elevate of palate bilaterally with “ah” noise
- Possible abnormalities: Loss of taste, dry mouth, anesthesia of pharynx; poor gag reflex; diminished or asymmetrical palate elevation (dysphagia, dysphonia, problems with secretions)
CN X
- Vagus nerve
- Function: Taste in epiglottis; sensation to epiglottis, larynx, trachea, colon, external ear, etc.; constriction of pharynx, larynx, & palatal muscles; Autonomic (parasympathetic) function to viscera of thorax and abdomen
CN X test
- Touch to ear
- Gag reflex
- Exam of soft palate
- Look for signs of autonomic imbalance
- Possible Impairments: Poor or absent gag reflex; persistent horseness; nasal quality to voice; dysphonia; dysphagia; dysarthria
CN XI
- Spinal Accessory Nerve
- Function: Head rotation and flexion (SCM); shoulder shrug (trapezius)
CN XI test
- Test strength of SCM & upper trapezius
- Possible impairments: weakness of shoulder shrug or head movements
CN XII
- Hypoglossal nerve
- Function: Skeletal movement of the tongue
CN XII test
- Inspect for asymmetry
- Protrude tongue
- Possible impairment: weakness, wasting of tongue, deviation to ipsilateral side on protrusion, dysphagia