Flashcards in Lecture 3: BSF Exam- Muscle Tone Deck (47)
Why is ROM important for a neuro exam?
will affect ACOM and affect activity
What is muscle tone?
resistance of muscle to passive elongation or stretch
neurological ready state of muscle to act
Why is muscle tone important?
supports posture, provides reflexive, energy efficient base for movement
What is muscle tone influenced by?
intrinsic mechanical or elastic properties of muscle fibers and connective tissue
and spinal reflex muscle contractions
What are two main types of muscle tone?
hypertonia- increase tone due to UMNL, hard resistance to passive stretch
hypotonia- decreased tone due to sometimes LMNL
Where does an UMNL occur?
injury or lesion to brain, brainstem, descending motor or pyramidal tract
Why does hypertonia happen?
increased excitability of alpha motor neurons (increased depolarization)
enhanced excitatory synaptic input (ms spindle or GTO)
What are two types of hypertonia?
spasticity and rigidity
What is spasticity?
an involuntary, velocity dependent, increased resistance to passive elongation
quick stretch results in increased resistance
What type of lesions usually cause spasticity?
pyramidal tract lesions in diseases like CP, CVA, MS, TBI
What is the clasp knife phenomenon?
strong resistance to initial passive movement followed by release of resistance
What is clonus?
cyclical, spasmodic alternating muscle contraction in response to sustained stretch
Why is spasticity a negative thing?
may lead to contracture, deformity, functional limitations, skin break down, weakness in both agonist and antagonist
Why might spasticity be helpful?
passive postural suport, may contribute to function in presence of reduced motor control
What factors will make spasticity worse?
infection, pressure sores, DVT, fatigue, bladder distention
What is PT management?
modalities, stretching, splinting, casting
but only temporary effect
What is rigidity?
increased resistance through range and not velocity dependent usually in both agonist and antagonist
What will rigidity look like in basal ganglia lesion?
cogwheel or leadpipe
What about brainstem lesions?
decerebrate or decorticate
What is decorticate?
reflects loss of corticol control (lesion above red nucleus) with flexed UE and extended LE
What is decerebrate?
reflects loss of inhibitory control of cortex and basal ganglia (below red nucleus) with full extension of all limbs and trunk
What is dystonia?
involuntary painful muscle contraction or spasm causing repetitive twisting motions, abnormal posture
What causes dystonia?
unknown currently, includes genetics, acquired, idiopathic
What is hypotonia associated with?
LMNL- anterior horn or peripheral nerve damage
UMNL- spinal shock or cerebellar lesion
chromosmal abnormalities- downs, muscle disease- muscular dystrophy
What else is associated with hypotonia?
reduced deep tendon reflexes
What does hypotonia result in?
poor posture, weakness, decreased function, pain
What will hypertonia look like?
increased muscle bulk, well defined and will feel taught and hard
What will hypo look like?
less definition, mushy feel
How to examine muscle tone?
lie pt in supine and perform PROM, don't hold muscle belly, make sure pt is relax and note ROM and end feels