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29 Cards in this Set
- Front
- Back
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What do cranial nerves do? |
Supply head with all of the functions supplied to the body by spinal nerves Include specialized functions such as vision, taste, hearing, and balance and autonomic functions. |
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How are cranial nerves tested ? |
Functional manipulation designed to elicit a deficit specific to a particular nerve. Tested in conjunction with symptoms |
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Why can PN and CN lesions involved one or more nerves? |
Their close proximity in the brain or brainstem and their and their peripheral pathways |
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What can loss of motor function of CN result from? |
Loss of central tracts that control motor functions (UMN) Loss of motor neurons themselves or their axons (LMN) |
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What is an UMN lesion? |
All motor system lesions that involve neurons or tracts that are not directly connected to muscles |
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What is a LMN lesion? |
Involve neurons or their axons that directly contact muscle |
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What are typical LMN symptoms? |
Flaccid Paralysis - relatively rapidly by atrophy of the muscle Fibrillations of motor units as a result of denervation Hypotonia - Decreased muscle tone Hypotreflexia/areflexia - weakening or absence of tendon reflexes |
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What occurs from LMN decifits |
Deficits are permanent, although if incomplete, some compensation/recovery can occur If functional loss results from more distal lesions of axons in a nerve, some limited functional regeneration of axons may be possible |
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What is UMN syndrome? |
result of denervation of motor neurons. A typical cause is stroke or other vascular occlusion in the brain or brainstem. The closer the lesion is to the origin of the tract, that all motor functions below the lesion are lost. |
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What are symptoms of UMN Lesions |
Weak and flaccid muscles followed by spasticity, hypertonia, hyperreflexia, clonus and altered cutaneous reflexes. |
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Describe recovery from UMN lesions? |
Recovery is more likely with cranial nerve motor nuclei because the motor cortex from both hemispheres usually innervates motor neurons on both sides |
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How do brain lesions typically present initially? |
Lesion on one side of the brain presents as initial weakenss on the contralateral side followed by recovery. Some disturbances of reflexes may occur where they can be examined |
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Describe the trigeminal nerve innervation |
Sensation to the face wtih the back of the head coered by C2-C3. CN5 carreis both epicritic and protopathic types of sensation |
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Describe lesions of epicritic systems? |
Will produce a loss or reduction in two point discrimination, the ability to feel vibration and the ability to tell the position of abody part in the absence of visual confirmation |
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Two point vs Kinesthetic testing? |
CN 5, 2pt Discrimination and vibration can be tested but Kin cannot |
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Describe lesions of the anterolateral system |
Produce contralateral loss of protopathic touch, pain, and temperature -pain is usually detected with a pin -Temp with tubes of cold and warm water |
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How are Cranial nerves 9 and 10 used to evaluated sensory info |
Usually done by triggering reflexes, such as gag and cough. BP and HR changes can also be examined, although these are not typically used to test CN functions |
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Cranial Nerve 1 Deficit |
Olfactory - Smell D: Anosmia Occludes one nostril, use an aromatic substance. ID Odor. |
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Cranial Nerve 2 deficit? |
Optic - vision D: Anopsia Check eyes individually for ability to detect objects in the visual field |
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Cranial Nerve 3 deficit |
Oculomotor Diplopia - double vision, external strabismus, loss of parallel gaze, ptosis Dilated pupil, loss of motor limb of light relfex with CN 2 Eye deviates out and down due to unopposed actions of remained muscles |
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Cranial Nerve 4 deficit |
Weakness looking down when eye is abducted, Difficulty reading, going down stairs Head may tilt away from the lesion side |
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Cranial Nerve 5 deficit |
Trigeminal Loss of sensation in skin of forehead Loss of sensory limb of blink reflex Loss of sensation over maxilla Loss of sensation in skin over mandible Weakness in chewing, jaw deviation toward lesioned nerve Decreased or absent jaw jerk reflex |
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Cranial Nerve 6 deficit |
Abducens Diplopia, internal strabismus, loss of lateral gaze |
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Cranial nerve 7 deficit |
Facial Corner of mouth droops, cannot close eye, loss of blink reflex Hyperacusis Alteration or loss of sense of taste Reduction in saliva output Dry eye Reduction in secretion |
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Cranial nerve 8 deficit |
Vestibulocochlear Sensorineural hearing loss Loss of balance, vertigo, nystagmus |
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Cranial Nerve 9 deficit |
Glossopharyngeal Loss of gag reflex, sinus reflex Sensory loss on posterior tongue reduction in salivation Swallowing difficulty Loss of taste to posterior tongue |
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Cranial nerve 10 deficit |
Vagus Palate droop, uvula pointing away from lesioned nerve Dysphagia, loss of gag reflex Hoarseness, dysphonia |
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Cranial nerve 11 Deficits |
Spinal Accessory Weakness turning head to opposite side Shoulder droop, difficulty combing hair |
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Cranial nerve 12 deficit |
Hypoglossal Tongue deviation on protrusion toward lesioned nerve Dysarthria (Difficulty speaking) |
