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45 Cards in this Set
- Front
- Back
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What are the 4 functions of the cranial nerves? |
-Supply motor innervation to the muscles of the head and face -Transmit somatosensory information from the head and face -Transmit special sensory information -Provide parasympathetic regulation |
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Where in the brainstem are the CN located? |
1 + 2 are not in the brainstem 3 + 4 - Midbrain 5, 6, 7, 8 - Pons 9, 10, 11, 12 - Medulla |
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Review slide 5 |
Function of CN |
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Why is most taste information attributed to olfactory? |
Because the information from taste buds is limited to chemoreceptors for salty, sweer, sour, umami, and bitter |
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Lesion of the olfactory nerve may cause... Testing olfactory |
Inability to smell -Smoking and/or mucus may interfere with function of olfactory nereve Test: Ask pt to ID strong odors: coffee, soap |
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Describe the Optic nerve |
Sensory Light striking the retina is converted into neural signals Visual signals are sent to the mid brain --Reflexive response of pupil --Awareness of light and dark --Orienting the head and eyes |
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Lesion of the optic nerve may cause... Testing Optic |
Ipsilateral blindness and loss of pupillary light reflex Test with snellen eye chart, visual field (peripheries) |
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Describe the Oculomotor, Trochlear, and Abducens nerves Testing CN 3, 4, & 6 |
Primarily Motor Innervate extra occular muscles that move the eye and control reflexive pupil constriction Test: Pupillary alignment, visual field, H-test, convergence, accomidation |
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Observation that indicates lesion of CN 3, 4, or 6 |
CN III -Ptosis -Diplopia -Eye deviates down and out -Deficits moving ips eye medially, down and up -Pupil dilation/loss of constriction -Loss of accommodation CN IV -Outward rotation and weakness of downward and inward gaze -Difficulty reading (vertical diplopia inc looking down) -Prevents activation of superior oblique CN VI -Stabismus (lazy eye) -Horizontal Diplopia -Eye deviates medially (lateral rectus paralysis) |
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Describe accomidation |
When viewing objects closer than 20cm, the ciliary muscle contracts, which inc the curvature of the lens Inc refraction of light rays to ensure that the focal point will be maintained on the retina |
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Pupillary vs Consensual reflex |
P: constriction of the pupil in the eye directly stimulated by the bright light C: Constriction of the pupil in the other eye |
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How to test Pupillary Constriction |
Dark room Shine light in pupil from the side -Assess tested side response (CN2) -Assess opposite side response (CN3) |
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How to test the Consensual light refledx |
Darken room Pt holds flat hand vertically between eyes -Ask pt to focus on distant object Move light in an arc from pupil to pupil -Hold light steady ~3s before moving to the other side Lesion of CN2 in right eye -Light in L eye causes constriction of R pupil (3) -Light moves to R eye, pupil appears to dilate (2) |
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Convergence vs Accommodation |
Convergence -Pt holds head in one place as object is brought closer towards nose, ask pt for when double vision starts. Accommodation -Hold pen 12in from nose -Ask pt to focus on pen (Lens thickens, pupil constricts) and then beyond the pen (Lens flattens, pupil dilates) |
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What does a complete lesion of the oculomotor nerve |
-Ptosis (drooping eyelid) -Ips eye looks outward and down -Diplopia -Deficits moving ips eye medially down and up -Loss of pupillary reflex and consensual response -to light |
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Describe a lesion affecting the medial longitudinal fasiculus |
Produces Internuclear Opthalmoplegia When the connection between the abducens nucleus and the oculomotor nucleus is interrupted, the contralateral eye moves normally but the eye ipsilateral to the lesion cannot adduct past the midline when the fellow eye moves laterally |
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3 branches of the Trigeminal nerve |
Opthalmic Maxillary Mandibular |
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How to test facial sensation of the trigeminal nerve |
Pt closes eyes -Sharp/dull testing - forehead, temples, jaw |
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How to test motor of trigeminal |
Open mouth Clench teeth Jaw jerk test |
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Describe a lesion of the trigeminal nerve |
Anesthesia of the area supplied by the ophthalmic, maxillary, or mandibular branch. Ophthalmic - blink reflex interrupted - prevents blinking in response to touch stimulation of the cornea Mandibular - Jaw will deviate toward the involved side when the mouth is opened. Masseter reflex is lost |
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Review Slide 27 |
Trigeminal Neuralgia |
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Testing the Facial nerve |
Facial symmetry Eyebrows up Eyes shut tight Big smile Show teeth Frown Puff cheeks |
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Lesion of the facial nerve |
LMN (Bells Palsy) - Side of face paralyzed -Forehead appears ironed out -Eye will not close -Flattening of the nasolabial fold UMN (Stroke) -Only the area of the face below the eyes is paralyzed |
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Review Slide 31 |
Bells Palsy |
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Describe the branches of the vestibulocochlear nerve |
Vestibular - transmits information related to head position and head movement Cochlear - branch transmits information related to hearing. |
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What three cortical areas are involved in processing auditory information |
Primary Auditory Cortex - conscious awareness of the intensity of sounds Auditory association cortex - Compares sounds with memories of other sounds a categorizes them as language music or noise Wernicke's Area - comprehension of spoken language |
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Effect of auditory information |
Orients head and eyes toward sounds Inc activity level throughout the CNS Provides conscious awareness and recognition |
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How to test CN 8 |
Webers: 512Hz tuning fork on forehead Rinne's: 512Hz tuning fork on mastoid behind ear then to ear once sound stops Stand behind pat and lightly rub fingers together and ask pt when they hear it |
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Effect of loss of hearing in one ear |
Interferes with the ability to locate sound |
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Conductive vs Sensorineural deafness |
C: Transmission of vibration is prevented in the outer or middle ear (ear wax) S: Less common than conductive deafness; damage of the receptor cells or cochlear nerve (old people) |
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What is Tinnitus - causes and treatment |
Infrequent, mild and high pitched ringing that last seconds to minutes is normal Causes -Meds, receptor stimulation, Central sensitiation after deafferentation Treatment -Hearing aid -Medication -Habituation -Transcranial magnetic stim of central auditory system |
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Describe Glossopharyngeal Nerve |
Sensory -Somatosensation of soft palate and pharynx -Taste receptors in posterior tongue Motor -Pharyngeal muscle and parotid salivary gland |
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Lesion of the Glossopharygeal nerve |
Complete lesion interrupts the afferent limb of both the gag reflex and the swallowing reflex Salivation is dec |
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Describe Vagus nerve |
Afferent and efferent innervation of larynx, pharynx, and viscera Dec HR, bronchoconstriction, affect speech production, inc digestive acctivity |
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Lesion of vagus nerve |
Difficulty speaking and swallowing Poor digestion Asymmetrical elevation of the palate Hoarsness |
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Testing Vocalization of CN 9 and 10 |
Sound of voice is hoarse or nasally Swallow small amount of water Cough Palate and uvula symmetry Gag reflex |
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Describe Speaking |
Mostly voluntary but can occur automatically in highly emotional contexts -In brain damage, limbic system may produce emotionally charged words Sounds Generated by Larynx (CN X) Articulated by jaw (5), Lips (7), Soft Palate (10), Tongue (12) |
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Describe the Accessory Nerver |
Motor Originates in upper cervical travels thru foramen magnum then exits through the jugular foramen. Provides innervation to the trap and SCM |
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Testing Accessory nerve |
Observe and palpate symmetry Shrug shoulders and hold against resistance Turn head and hold against resistance -L rot tests R SCM |
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Lesion of the accessory nerve |
Complete lesion paralyzes the ipsilateral SCM and Trap UMN lesions cause paresis rather than paralysis because cortical innervation is bilateral and the muscles become hypertonic. |
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Describe Hypoglossal nerve |
Innervation to intrinsic and extrinsic muscle of the ipsilateral tongue Controlled by both voluntary and reflexive neural circuits |
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Testing Hypoglossal Nerve |
Listen to articulation Inspect tongue for symmetry, fasciculation Protrude tongue (deviates toward affect side) Run tongue around lips |
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Lesion of the hypoglossal nerve |
Atrophy of the ipsilateral tongue Tongue protrudes ipsilateral Wasting of contralateral tongue Problems with tongue control result in difficulty speaking and swallowing |
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Describe dysphagia |
Difficulty with swallowing -Fq choking -Lack of awareness of food in one side of the mouth -Food coming out of the nose CN V, VII, IX, X, and/or XII dysfunction |
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Describe Dysarthria |
Poor control of the speech muscles Only vocal speech is affected, pt can read and write fine CN V, VII, X, and/or XII |
