Sensory system Flashcards
What types of sensation is transmitted by the dorsal columns?
Fine, discriminative touch, proprioception, vibration
What fibers are there in the dorsal columns?
large myelinated fibers
Where do the dorsal columns deccusate?
Medulla:
nucleus gracilis ( lower limbs)
nucleus nucleus cuneatus (upper limbs)
What is the course and destination of the dorsal columns?
medulla(deccusates) - medial lemiscus - thalamus - sensory cortex
What types of sensation is transmitted by the spinothalamic tracts?
poorly localized touch, pain, temperature
What fibers are there in the spinothalamic tracts?
small non-myelinated fibers (first affected by local anestheisa)
Where do the spinothalamic tracts deccusate?
at the level of cord entry
What is the course and destination of the spinothalamic tracts?
Lateral (fast pain, temp) cord
Anterior (touch, slow pain) cord
- via the brainstemreticular formation
- thalamus
- sensory cortex
What are the five nuclei in the thalamus?
Sensory Motor Limbic Association Nonspecific
What are common causes of single nerve lesions?(5)
Diabetes, RA, hypothyroidism, trauma, vascular
What are common causes of glove and stocking polyneuropathy? (9)
diabetes uremia malnutrition paraproteinemias cancer colagenosis toxings inflammation inherited neuropathies (i.e Charcot-Marie-Tooth)
What typically causes nerve root lesions?(2)
disc compression or tumor
What are causes of complete cord lesion?(4)
trauma, tumor, MS, inflammation
What are causes of hemisection of the spinal cord?(3)
inflammation, MS, intraspinal tumor
What is “central cord syndrome”?
And what are the typical causes(2)
Loss of temp. and pain sensation AT the level of the lesion (typically cervical)
large lesion may affect whole body under lesion
- syringomyelia, intramedullary tumors
Isolated lesion of the dorsal columns are typically a result of which two diseases?
Vit B12 deficiency Tabes dorsalis (syphilis)
What is anterior spinal syndrome?
- Loss of pain and temp. sensation below the lesion
- caused by occlusion of ant. spinal artery(Adamkiewicz a.)
A lesion in the sensory pathways of the brainstem will produce what sensory symptoms?
ipsilateral loss on the face
contralateral loss on trunk and limbs
A lesion in the sensory pathways of the thalamus will produce what sensory symptoms?
loss on all sensation on the contralateral side
A lesion in the sensory pathways of the internal capsule will produce what sensory symptoms?
loss on all sensation on the contralateral side
A lesion in sensory cortex will produce what sensory symptoms?
no superficial sensory disturbances
unable to localize stimuli
loss of sterognosia(object shape) and discrimination
What is the clinical presentation of Oculomotor lesion?
Lateral and downward eye
diplopia
Dilated and fixed pupil
Ptosis
What nuclei is involved in the light reflex and the accomodation reflex
Edinger westfal nucleus
What is the clinical manifestation of Horner syndrome?
Unilateral: Miosis ptosis anhidrosis endopthalmos vasodilation
How does trochlear nerve palsy present clinically?
Head tilt and chin tuck to contralateral side
What is internuclear ophtalmoplegia
lesion to LMF
problems with adduction on ipsilateral side and vertical nystagmus on other side
bilateral internuclear opthalmoplegia is typical for which disease?
MS
A lesion in the trigeminal nerve will result i what clinical findings?(3)
Pain/loss of sensation
loss of corneal reflex (V1)
Paralysis of ipsilateral chewing muscles
What can be the clinical findings of facial nerve lesions? (5)
Paralysis of ipsilateral facial muscles (peripheral lesion)
Paralysis of lower contralateral face (central lesion)
Hyperacusis
Dry eyes
Dry mouth
loss of taste (ant 2/3) if proximal to chorda tympani
What are the clinical signs of Vestibular nerve lesion?(4)
vertigo with falling to affected side
inabillity to maintain vertical posture
nystagmus and blurred vision
nausea and vomiting
What are the clinical signs of Cochlear nerve lesion?(2)
Diminished hearing/deafness
Tinnitus
What are the clinical signs of Glossopharyngeal lesion?(4)
Palatal palsy
Dysphagia
Loss of reflexes from carotid body and sinus
loss of taste/touch on post. third of tongue
What are the clinical signs of Vagus nerve lesion?(4)
Dysphagia
palatal palsy(uvula deviates to opposite side)
Hoarseness
loss of vagal cardio/gastro/resp reflexes
What are clinical signs of Spinal Accessory nerve lesion? (3)
weakness of head rotation
weakness of shoulder shrugging
vocal cord paralysis and hoarseness (carry vagal fibers)
What are clinical signs of Hypoglossal nerve lesion?(3)
Paralysis and atrophy ipsilaterally
Dysarthria
Dysphagia
Where is the nucles of CN3 located?
midbrain
Where are the nuclei of CN 4,5,6,78 located?
Pons (CN5 also in medulla)
Where are the nuclei of CN 10,12 located?
medulla
Where are the nuclei of CN 11?
spinal cord
What are the signs of bulbar palsy?(5)
Dysarthria Dysphagia diminished mandibular reflex paresis of pharynx and palate loss of gag reflex paralysed tongue
where is the lesion in bulbar palsy?
CN 5,9,10,12
What are the signs of pseudobulbar palsy?(7)
Dysarthria Dysphagia increased mandibular reflex increased pharyngeal reflex paralysis of tongue(no atrophy or fasiculations) Affect incontinence Fronal release ( primitive reflexes)
Where is the lesion in pseudobulbar palsy?
Bilateral lesion of corticonuclear fibers
