Neurological Examination of Sensation, Reflexes, and Motor Function Flashcards
what are the three types of primary or basic sensation
- exteroceptive-external stimuli; light touch, pain temp
- proprioceptive-stimuli from muscles, tendons, ligaments, joints, in relation to position and mvmt of body, limbs and digits. important for balance
- interoceptive-internal stimuli affecting visceral organs
cortical or combined sensation
-simultaneous perception of several basic stimuli integrated and interpreted at the cortical level
define paresthesia
pins and needles
define dysesthesia
uncomfy hypersensitivity to non-noxious stimuli
when do paresthesia and dysesthesias pop up
with various lesions of the sensory system, particularly with peripheral nerve disorders
clinical eval of exteroceptive sensation
- light touch with cotton wisp
- blunted safety pin for pain
- cool metallic for temp sensation
how is vibration sensation assesed
128hz tuning fork to bony structure (ankle or knuckle)
clinical eval of proprioceptive sensation/position sense
raise/lower finger or toe…up/down
define stereognosis
tactile recognition of familiar object with eyes closed
define graphesthesia
id of numbers traced on palm with pts eyes closed
extinction on dbl simultaneous stimulation
d/t a contra parietal cortical lesion
two pt discrimination/fine touch
ability to detect simultaneous application of two sharp points separated by a small distance–usually a cortical sensation
in disorders of periph nerves; larger vs smaller sensory fibers
- larger, more myelinated=impaired position sense and vibration
- smaller, less myelinated=impaired temp and pain (or pin)
lesions of posterior or dorsal columns
deficits in position sense, vibration, and 2pt discrimination
lesions of spinothalamic tract
deficits in pain (pin) sensation and temp
mononeuropathy vs. polyneuropathy (peripheral neuropathy)
- mono: sensation is decreased or lost in the territory of one peripheral nerve
- poly: sensation is dec in several peripheral nerves=stocking and glove
spinal cord lesions (myelopathies)
-dissociation of sensation is characteristic (with loss of one modality of sensation with preservation of another)
intramedullary spinal cord lesions
occur within the sc parenchyma causing suspended or vestlike sensory loss and sacral (dermatome) sparing of sensory deficit
extramedullary spinal cord lesions
-compress the sc from outside, creating an initial sensory loss in sacral segments, progressing up “to a level” b/c of lamination of the STT
what causes a hemisensory (hemibody) deficit of basic sensations on the right or left side of the body including the face
contralateral THALAMIC lesion or involvement of sensory pathways to the contra parietal lobe
what does a lesions in the contra parietal sensory cortex cause
isolated or predominant deficits involving cortical or combined sensation typically occur on one side of the body
C5
lateral shoulder
C6
thumb
C7
index/middle fingers
C8,T1
ring/little fingers
T4
teat pore (nipple)
T10
umbilicus (belly butTEN)
L3,4
anterior thigh
L5
dorsal foot
S1
lateral foot/sole
reflex
quick automatic replicable motor response or muscle contraction provoked by a stimulus
muscle stretch reflexes (MSR)
-elicited by hammer tap of selected tendon
tendon tap
- causes passive stretching of its muscle and neuromuscular spindles
- activates Ia sensory nerve fibers (afferent reflex arc)
- depolarization of alpha motor neurons (anterior horn cells) at the root level of the sc
- contraction on muscle fiver and visible muscle twitch (efferent reflex arc)
define clonus
reflex followed by repetitive jerking movements
MSR
- biceps: C5,6 (pick up sticks)
- brachioradialis (radial): C5,6
- triceps: C7,8 (lay them straight)
- finger flexors: C8,T1
- quadriceps (patellar, knee jerk): L2,3,4 (kick the door)
- achilles (ankle jerk): S1,2 (buckle my shoe)
abnormalities of MSR
- hyporeflexia/areflexia in polyneuropathy or radiculopathy
- hyperreflexia in UMN lesion (inhibitory effect on local reflex circuit from descending supraspinal tracts is lessened)
- asymmetrical hyperreflexia on one side of body 2/2 UMN lesion (corticospinal tract)
CN-mediated superficial reflexes
-characteristically consensual, w/ b/l response to a u/l stimulus (ex corneal blink reflex)
weird cutaneous reflexes that dont involve CN
abdominal reflex and cremasteric reflex
CN superficial reflexes (4 total)–UNILATERAL afferent and BILATERAL efferent
- pupillary: 2 sine light, 3 pupils constrict
- corneal: 5 touch cornea, 7 eyes blink
- palpebral: 5 touch eyelid/lash, 7 eyes blink
- gag (pharyngeal): 9 touch pharynx, 10 gag
Babinski sign
- most important and reliable pathological reflex
- indicates an UMN (corticospinal tract) lesion in the adult
- nml in kids 1-2yo
- not a monosynaptic MSR**
meningeal signs
Kernig-when resistance to fully extending pt knee
Brudzinski-pts hips and knees flex after passive flex of neck
Lasegue-sign of nerve root irritation or compression
pronator drift
suggests a subtle proximal upper limb weakness from a corticospinal tract lesion
weakness of one limb
- partial: monoparesis
- complete: monoplegia
myelopathic weakness
- from a b/l sc lesion may involve both lower limbs from a lesion at the thoracic level
- partial: paraparesis
- complete: paraplegia
all four limbs weal from a cervical sc lesion
partial: quadriparesis
complete: quadriplegia
UMN lesion in ipsi sc or contra brain or brainstem causes
partial (hemiparetic) or complete (hemiplegic) weakness of the upper and lower limbs on one side
in a pt with muscle dz what does the typical myopathic pattern of weakness involve
proximal limbs at shoulders and hips
in a pt with polyneuropathy (peripheral neuropathy) what is the patter of neuropathic weakness
distal-involving feet and later hands
what are the two types of hypertonicity
- spasticity-unequal between agonist and antagonist muscles…clasp-knife spasticity
- indicates UMN lesions involving pyramidal or corticospinal tract - rigidity-lead pipe rigidity; constant in agonist and antagonist muscles
- indicates lesion in EPS system
- cogwheel rigidity-if tremor is present, passive limbs do this
hypotonicity
decreased muscle tone usually from an afferent sensory or LMN lesion
define fasciculation
spontaneous d/c of a motor unit (which consists of its LMN, axon, and all the muscle fibers it controls)
- sign of denervation from a LMN lesion
- can also occur with muscle fatigue
define fibrillation
- spontaneous twitch of an individual muscle fiber-only visible in tongue
- sign of denervation from a LMN lesion
spinal or neurogenic shock
in a sudden severe sc injury (typically from trauma), expected UMN clinical signs are initially absent only to gradually emerge days or weeks later
-therefore, in spinal shock paralysis is initially accompanied by diffuse hypotonia and areflexia
