EXAM 2 Flashcards
what are the two major categories/groups of senses?
somatic senses
special senses
what are somatic senses?
usually single receptors in the skin (cutaneous) or muscle
what are special senses?
more elaborate sensors (ex: in the eye or ear)
what fibers detect light touch?
what tract?
A beta fibers
A delta fibers
anterior spinothalamic tract
what fibers detect pain?
A delta fibers
C fibers
what fibers detect temperature?
A delta
C fibers
what fibers detect proprioception
A beta fibers
what is sensory testing used for in PT?
as a part of neurological examination or screening
gives info regarding status of neurological system for primary senses as well as those under cortical control
(PT guided towards area of focus by pt’s medical history)
how is PRIMARY sensation evaluated?
having pt identify various sensory stimuli
what are the 4 primary sensations?
superficial (light) touch
superficial pain (sharp sensation)
temperature and deep pressure
vibration
what is cortical discrimination?
sensory functions test cognitive ability INTERPRET sensations associated
what is cortical discrimination often associated with?
coordination abilities
what type of lesion would be suspected if there was inability to perform cortical discrimination tests?
lesion in the cortex or the posterior columns of the spinal cord
more typically for head/brain injuries or space-occupying lesions (CNS cancers)
what are some of the tests for cortical discrimination?
stereognosis two-point discrimination graphesthesia point location proprioception
what is stereognosis
ability to identify by touch manipulation alone
what will deficits in cortical discrimination alter?
balance, coordination, fine motor skills
what are some considerations for safety with cortical discrimination?
gait
transfers
functional mobility
selection of assistive devices
why test sensation?
- identify various sensory stimuli (intact, impaired/diminished, absent)
- for differential diagnosis
- assess type and amount of sensory impairment for clinical decision-making
- identify risk factors for safety
- monitor changes in sensory status
what types of patients often have sensory problems?
MS DM spinal cord injury radiculopahty and peripheral nerve entrapment syndromes CVA traumatic brain injury CP elderly burns scar tissue/skin grafts
what are some of the principles of clinical sensory testing?
- position pt comfortably
- explain and demonstrate what you will be doing
- test DIRECTLY on skin (NOT through clothing)
- have pt close eyes
- test normal sensation first, then move toward impaired or absent sensation
- map out the impaired area(s) (helps distinguish between dermatomal vs peripheral nerve involvement)
- clean all equipment before using on another pt
how can you test light touch?
use cotton ball
how can you test sharp/dull?
use a safety pin or other sharp instrument, and a dull instrument
what tract is light touch carried on
anterior spinothalamic tract
what tract is sharp/dull sensation carried on
lateral spinothalamic tract
how can you test temperature sensation?
water in test tubes of differing temperatures
used crushed ice and water if available, and hot tap water
what tract is temperature carried on?
lateral spinothalamic
how can you test vibration sensation?
using a tuning fork
test over bony prominences
what pathway is vibration sense carried on?
dorsal column (medial lemniscus)
what pt’s is vibration loss often seen in?
pt’s with DM and peripheral neuropathy
how do you test protective sensation?
Semmes-Weinstein monofilament testing
often used in cases of dorsal sensory loss (feet)
-as in pt’s with DM
the thicker the filament, the more likely pt’s will sense pressure (compare with normal populations)
what are deep tendon reflexes? (DTR)
- myotatic or muscle stretch reflexes
- monosynpatic
- consist of afferent and efferent portion
- synapse is in SC
Function of muscle spindles are Golgi Tendon Organs?
- CNS requires info regarding muscle length and tension
- spindles detect changes in STRETCH or length of muscle
- GTO detect changes in TENSION
- SC reflexively uses this info
what is an extrafusal muscle fiber?
ordinary skeletal muscle fiber
contractile tissue
what is an intrafusal muscle fiber?
specialized fibers of the muscle spindle
what is the muscle spindle?
elongated structure within the muscle, running parallel to skeletal muscle fibers
- encapsulated within a gelatinous fluid
- non-contractile center, but with polar regions that are contractile
what are the types of muscle spindles?
nuclear chain
nuclear bag
what is a nuclear chain muscle spindle?
nuclei are in single file, or in a series
what is a nuclear bag muscle spindle?
nuclei are in clusters in the middle of the spindle
they are either:
- dynamic: measures stretch “in progress”
- static: measures stretch “on hold”
what is the afferent pathway
pathway TOWARD the spinal cord (majority of time is sensory information)
afferents are labeled as Ia fibers from nuclear chain OR nuclear bag, or as II fibers from nuclear chain
where are the sensory endings located?
central (non-contractile region of the spindle)
what is the efferent pathway?
pathway AWAY FROM the spinal cord (majority of time it is motor information)
what does the alpha motor neuron excite?
skeletal muscle
extrafusal muscle fibers
what does the gamma motor neuron excite?
muscle spindle motor fibers
intrafusal muscle fibers
- located in polar regions
- makes the spindle contract so it can respond again to stretch
what happens during the stretch reflex?
- stretch occurs in muscle, lengthening it
- spindles imbedded in the muscle intrafusal fiber are lengthen as well
- triggers sensory endings in non-contractile portion to fire, sending a message to the spinal cord via Ia or II fibers
how do you test a pt’s deep tendon reflexes?
- have pt as relaxed as possible
- -position so that part to be tested is completely supported (no contraction by pt)
- distract the pt if necessary
- -talk to pt
- use reflex hammer correctly
- put muscle to be tested on slight stretch
how do you grade a deep tendon reflex?
0 = no response 1+ = sluggish or diminished 2+ = active or expected response (NORMAL) 3+ = more brisk than expected, slightly hyperactive 4+ = brisk, hyperactive, clonus
is hypo-reflexive UMN or LMN?
LMN lesion
PNS
is hyper-reflexive UMN or LMN?
UMN lesion
CNS
what are some forms of superficial heat?
hot moist pack (HMP)
paraffin
fluidotherapy
infrared and UV (heat lamp)
what are some forms of deep heat?
thermal ultrasound
thermal diathermy
what are some forms of cryotherapy?
cold pack (gel) ice pack (cubed or crushed ice) cryostick ice massage cold spray
what are the afferent axons (fiber)?
Ia (chain and bag)
II (chain)
what are the efferent axons ?
alpha (extrafusal)
gamma (intrafusal)
true/false - thermotherapy is often used for treating muscle spasms.
true
what is a muscle spasm?
a tonic phenomenon - muscle is in constant contraction, or increased tone
how does heat cause muscle relaxation? (3 mechanisms)
- decreased firing rate from type II fibers (results in decreased stimulus to tonic alpha motor nerve (AMN))
- increased firing from GTO (Ib) receptors (which synapse with AMN and are inhibitory
- decreased gamma efferent firing (results in less stretch of the receptor of the spindle, causing decreased afferent firing and decreased AMN stimulation
what are normal core and skin temperatures of head, neck, trunk
37 C
98 F
what are normal core and skin temperatures of fingers/hands
32-35 C
89-98 F
what are normal core and skin temperatures of feet/toes?
28-32 C
82-90 F
what factors determine threshold for thermal injury?
- location and extent (of heat application)
- intensity of temperature differential (body versus thermal/cryo agent)
- duration of exposure
what is the general rule for local critical temperatures?
maximum temp of 43-45 C (110-113 F)
no longer than 30 minutes!
(consider individual factors for each patient)
what are core critical temperatures?
temps above 42 C (107 F)
temps below 25 C (77 F)
can be fatal for even short periods of time
what are the hemodynamic effects of cold?
- immediate vasoconstriction o cutaneous blood vessels
- reduction in blood flow
VALUE: reduce blood loss
what are the mechanisms of the hemodynamic effects of cold?
- direct action of cold on smooth muscle
- reflex cutaneous vasoconstriction
what is the value of cold hemodynamic effects?
reduce blood loss
what are the direct actions of the hemodynamic effects of cold?
cold causes vascular smith muscle to contract, which reduces vessel diameter
