Exam #5 Info Flashcards
Cocontraction
Partial or full contraction of muscles on both sides of a joint or “around” a “body segment”
Static Cocontraction
Stiffly lock a joint
Dynamic Cocontraction
Control movement of a joint
Two types of lower motor neurons
Alpha motor neuronsGamma motor neurons
Alpha motor neurons
A-alphaExtrafusalGo to the sarcomeres that make the muscle shorten
Gamma motor neurons
A-gammaIntrafusalGo to the muscle spindles
Motor units
One alpha motor neuron and all muscle fibers it connects to
T/F: One motor unit is either fast or slow twitch; NOT mixed
True
Order of Recruitment (Henneman’s size principle)
Slow twitch firstFast as speed and/or intensity increase
Exceptions to order of recruitment
Need explosive/high level levels of force right away
Gross motor control
Many muscle fibers for each motor axon (LMN)
Fine motor control
Few muscle fibers for each motor axon (LMN)
Alpha-gamma coactivation DEFINITION
Voluntary movement causes UMN to send parallel messages to alpha and gamma motor neurons-Alpha message: move muscle, contract-Gamma message: keep spindle sensitive to stretch
Alpha-gamma coactivation FUNCTION
Keeps spindle sensitive during movement
Sources of convergence of information on alpha motorneurons
1) From an UMN with a message to move (movement pathway)2) From a sensory receptor (mechanoreceptors, spindles, touch/pain receptors)
Motor Neuron Pools
Gray matterVentral hornAxons from a pool project to a single muscle
Vertical organization of Motor Neuron Pools
Single pool may include several spinal levels and several myotomes
Medial Motor Neuron Pools
Axial and proximal muscles
Reciprocal inhibition
When the brain makes one muscle contract, it makes the opposite muscle contract
Reciprocal inhibition connections
Upper motor neurons –> alpha motorneuronsMuscle spindle afferents –> alpha motorneurons
Muscle synergies
Many muscles working together
Muscle synergies are created by…
Activation of multiple motor neurons-brain activates more UMN to contract many LMNBranching of upper motor neurons-UMN branch and go to several musclesInterneuron networks-little networks of neurons that increase connections between muscles
“Normal” muscle synergies
Group of muscles that work under control for a functional outcome
“Abnormal” muscle synergies
Group of muscles that work without control and do not produce a functional outcome
Role of GTO in movement
GTO transmit message of force/tension and that information is used by your brain to control movement
Phasic stretch reflex
Monosynaptic reflex, muscle stretch reflex and DTRStimulus: stretch of muscle spindle primary endings –> Ia fiberMonosynaptic connection w/ alpha motor neurons (same m)Response = brief facilitation or activation of alpha motor neurons (same m)
Withdrawal reflex
Stimulus: activation of nociceptor –> Adelta fiberMultisynaptic connection w/ alpha motor neurons (many m)Response = automatic withdrawal of limb with pain
Where do UMN director tracts start and end?
Start: above the brainstemEnd: ventral horn of spinal cord
Medial division of director tracts project..
More to LMN or proximal arm and leg”Move any way I want”
Lateral division of director tracts project…
More to LMN of distal arm and leg”Move any way I want”
Where do UMN helper tracts start and end?
Start: in the brainstemEnd: ventral horn of spinal cord
Medial division of helper tracts project..
More to LMN of proximal arm and leg “Help me move”
Lateral division of helper tracts project..
More to LMN of distal arm and leg”Help me move”
Director tracts are the ___ level of voluntary control and helper tracts are the ___ level of voluntary control.
HighestLowest
T/F: Director UMNs help control activation of helper UMNs in brainstem.
True
Alpha-gamma coactivation MECHANISM
Every LMN splits to serve alpha and gamma motor neurons
Lateral Motor Neuron Pools
Distal muscles
Anterior Motor Neuron Pools
Extensors
Posterior Motor Neuron Pools
Flexors
Lateral Corticospinal Tract
DirectorLateral DivisionContains 90% of UMN that start in precentral gyrus
Where does the Lateral Corticospinal Tract Start and End?
Start: precentral gyrus –> Lateral aspect of ant horn of spinal cordEnd: Lateral aspect of ant horn of spinal cord –> Extrafusal muscle fibers of more distal musclesSynapse: ventral horn
What does the Lateral Corticospinal Tract do?
Produces fractionation of movement (fine motor control)
Rubrospinal Tract
HelperLateral Division–>distal musclesFacilitates flexorsHelps pick stuff up against gravity
Medial Corticospinal Tract
DirectorMedial DivisionProximal musclesContains 10% of pre central gyrus neurons that DO NOT cross the midline
Reticulospinal Tract
HelperMedial DivisionExtensorsHold me up against gravity
Medial Vestibulospinal Tract
Balance and EquilibriumHelperMedial divisionExtensorsHold me up against gravityNeck and upper body postural muscles
Lateral Vestibulospinal Tract
Balance and EquilibriumHelperMedial DivisionExtensorsHold me up against gravityDistal muscles of legs
Nonspecific Activation System
Some UMN from brainstem simply control relative excitation
Paresis
Weakness, difficulty moving
Paralysis
Inability to move
Atrophy
Shrinking of muscles
Atrophy: Disuse
Don’t exercise a muscle and it shrinks
Atrophy: Denervation
Muscle loses its connection with a LMN and wastes away
Muscle Spasms and Muscle Cramps
Involuntary muscular contraction that starts at the muscular levelMetabolic reasons: dehydration, electrolyte imbalance, muscle overwork, too much calcium in the muscleNOT nervous system origin
Fasciculations
Contraction of an entire motor unitAxon is spontaneously active and the motor unit jumps
Myoclonus
Rhythmic, involuntary muscular contraction
Tremor
Shaking or back and forth movement of a limb
Tremors can be during…
Rest (Parkinson’s Disease)ORIntention (Cerebellar Problems)
Fibrillations
Spontaneous depolarization of one denervated muscle fiberNerves uncouple from muscle fibers
Hypotonia (flaccidity)
Decreased muscle tone
Hypertonia
Increased muscle tone
Shock
Period of time post nervous system trauma when motor units are unexcitable or “in shock”Cerebral OR Spinal
Signs and Symptoms of LMN Disorders (5)
Loss of reflexes (stretch and cutaneous)Atrophy of denervationDisorders of muscle tone (hypotonia/flaccidity)Paralysis (“flaccid” paralysis)Fibrillations
Examples of LMN Disorders
Peripheral nerve injury (carpal tunnel syndrome)Amyotrophic Lateral Sclerosis (ALS) (Lou-Gehrig’s Disease)
Signs and Symptoms of UMN Syndrome (3)
Paresis/Paralysis (“Spastic” paralysis)Loss of fractionation of movementAbnormal reflexes (cutaneous, muscle stretch hyperreflexia, clonus, clasp-knife response)
“Spastic” Paralysis
Stretch reflex hyperreflexia
Loss of fractionation of movement
Lateral corticospinal tract is no longer controlling the distal muscles of the arms/legs
Abnormal cutaneous reflexes
Exaggerated or hyperreflexive withdrawal to painEX: Babinksi Reflex
Muscle stretch hyperreflexia
Exaggerated muscular response to a quick stretchMore UMN damage = stronger response
Clonus
Repeated stretch hyperreflexia
Clasp-knife response
Catch and releaseMuscle stretch hyperreflexia that relaxes/goes away
Spastic hypertonia
Muscle stretch hyperreflexiaVelocity dependent
Rigid hypertonia
Some UMN damage causes the UMN to send inappropriate signals pretty much all the timeVelocity-independent EX: Parkinson’s, brain trauma
Decerebrate rigidity
Unconscious tonic hypertonia in extensors for the arm/legHelpers are unconsciously extending the arms/legs
Decorticate rigidity
Abnormal tonic flexion of arms and abnormal tonic extension of legsRubrospinal helpers flexing the arms and vestibulospinal helpers extending the legs
Muscle overactivity
Excess tone that is activity dependentHelpers turned on without direction causes too much toneEX: stroke
Disorders of muscle contraction (6)
Delayed initiationSlow force productionProlonged contraction timeDisordered coordination of agonists and antagonistsDecreased fractionationAbnormal muscle synergies
Spasticity (neural) “hyperstiffness”
Velocity dependent increase in strength of the phasic stretch reflexUMN damage lets LMN reflex loop run wild
Rigidity (neural) “hyperstiffness”
Velocity independent increase in resting muscle toneUMN damage results in abnormal, tonic signals to LMNEX: brain trauma or Parkinson’s
Muscle overactivity (neural) “hyperstiffness”
Activity dependent increase in muscle tone that is inappropriate for the taskUMN damage results in abnormal signals to LMN during activity
Myoplastic hyperstiffness (mechanical)
Excessive resistance to muscle stretch that is due to increased intrinsic stiffness along with connective tissue tightness (including contracture)Resistance is not due to increased muscle “tone”
Caudate of the basal ganglia
Input from “prefrontal” cortexCognitive link Gets the message: this is what I want to doUnderstands how you want to move
Putamen of the basal ganglia
Input from primary motor cortex and motor planning cortexMovement linkKnows what you are doing now and what the environment is like
Globus Pallidus and Subthalamic Nucleus of the basal ganglia
Processors
Substantia Nigra
In the midbrainContains dopamine producing neurons that power the basal ganglia circuit
Compacta of the Substantia Nigra
DopamineCritical for producing voluntary movement
The basal ganglia has projections to…
Motor planning areas of the cerebral cortexThe midbrain
The projection of the basal ganglia to the motor planning area of the cerebral cortex goes through ____ and connects ____.
Motor thalamusBasal ganglia and to directors
The projection of the basal ganglia to the brainstem goes through ____ and connects ____.
Pedunculopontine nucleus of the midbrainBasal ganglia to helper motor neurons of the brainstem
What are the 4 functions of the basal ganglia motor loop?
Sequencing movementsRegulating muscle toneRegulating muscle forceFacilitating or inhibiting specific motor synergies
What is the function of the oculomotor loop of the basal ganglia?
Direct eye movement
What is the function of the executive loop of the basal ganglia?
Goal directed behavior
What is the function of the behavioral flexibility and control loop of the basal ganglia?
Social appropriateness
What is the function of the limbic loop of the basal ganglia?
Emotions
What kind of output messages does the basal ganglia send?
Inhibitory
What type of disorder is Parkinson’s Disease?
Hypokinetic
Parkinson’s Disease Pathophysiology
Death of dopamine producing cells
What does Parkinson’s disease lead to?
INCREASED inhibition of motor thalamus –> DECREASED voluntary movementINCREASE inhibition of pedunculopontine muscles –> EXCESSIVE contraction of both flexor and extensor postural muscles
7 signs of Parkinson’s Disease
Akinesia/hypokinesiaRigidity (cog wheel)Freezing during movementVisuoperceptive impairmentsPostural instabilityResting tremorNon-motor signs
What type of disorder is Huntington’s Disease?
Hyperkinetic disorder
Huntington’s Disease Pathophysiology
Degeneration of basal ganglia “input modules” and cerebral cortex
What does Huntington’s Disease lead to?
DECREASED inhibition of motor thalamus –> involuntary muscle contractionsDECREASED inhibition of pedunculopontine nucleus –> insufficient contraction of both flexor and extensor postural muscles
2 Signs of Huntington’s Disease
ChoreaDimentia
Chorea
Twisting or writhing of the extremities
Inputs to cerebellar cortex
Primarily proprioception and somatosensationSpinocerebellar
Midline vermis of the cerebellum controls…
Central core
Paravermal hemisphere of the cerebellum controls…
Proximal extremity muscles
Lateral hemisphere of the cerebellum controls…
Distal parts, especially hands and feet
Vestibulocerebellum
Flocculonodular lobeInner earEquilibrium and balanceInfluences eye movement and postural muscles
Spinocerebellum
Controls movement of the limbsMidline core and proximal musclesControl ongoing movement via the brainstem descending tracts
Cerebrocerebellum
Fine, distal, voluntary movementsCoordination of voluntary musclesPlanning of movementsAbility to judge time intervals and produce accurate rhythms
5 global functions of the cerebellum
Contributes to muscle toneHelps plan and control movementsSpeedDirectionTiming
Name the 3 cerebellar peduncles
SuperiorMiddleInferior
Superior cerebellar peduncle
Most of cerebellar efferentOutput to brainstem and cortical UMNUnconscious and conscious movement correction
Middle cerebellar peduncle
Afferent from corticopontocerebellar fibersInput to cerebellumXerox copy of the movement plan
Inferior cerebellar peduncle
Afferent from spinal cord and brainstemInput from spinocerebellar tractCarries the message of what I’m actually doing
Summary of the functions of the cerebellum
Comparing actual motor output to the intended movementAdjusting actual motor output if there is a discrepancy
Name the two general signs of Cerebellar Clinical Disorders
HypotoniaAtaxia
Are signs ipsilateral or contralateral to the side of damage in the cerebellum?
Ipsilateral
Lesions of the vestibulocerebellum result in…
Abnormal eye movementsDysequilibriumTruncal ataxia
Dysequilibrium
Imbalance
Truncal ataxia
Trouble setting and controlling the core and most proximal muscles
Lesions of paravermis and cerebrocerebellum result in…
Dysarthria
Dysarthria
Problem with mechanical production of words and sounds
Lesions of the spinocerebellum result in…
Ataxia, wide-based gait
Lesions of the spinocerebellum (cerebrocerebellum) result in…
DysdiadokokinesiaDysmetriaAction tremor
Dysdiadokokinesia
Problem with rapid alternating movement
Dysmetria
Trouble hitting a target that you reach for with hands or feet
4 general treatment strategies for cerebellar disorders
Slow down movementThink about movingSimplify movementsSee and feel movements
5 ways to distinguish cerebellar ataxia from somatosensory ataxia
Stance with eyes open vs eyes closedVoluntary movement with eyes open vs eyes closedConscious proprioception testingVibration sense testingAnkle reflex testing
Spinal Nerve
Joining of the rootsOne place where all the sensory, motor, and autonomic for one spinal level are gathered togetherDividing line between central and peripheral
What pattern does a spinal nerve display when damaged?
Myotomal or dermatomal
Name the 3 Peripheral N Rami
Ventral/AnteriorDorsal/Posterior”Communicating”
Ventral/Anterior Peripheral Rami
Front of the body including the arms and legsAll motor, sensory and autonomic to the front of the body (legs, front of torso and all of the arms)Enter and make up the various nerve plexusesThicker than the dorsal
Dorsal/Posterior Peripheral Rami
Back of the body NOT including the arms and legsGo to the back (turtle shell) of the bodyMuch smaller than the ventral
“Communicating” Peripheral N Rami
To and from paravertebral sympathetic gangliaCommunicating sympathetics to and from the paravertebral gangliaParavertebral ganglia has a synapse between pre and post ganglionic
Peripheral nerve distal axon projections are…
Superficial (to skin) and deep (to bones, joints and muscles)
What pattern does a peripheral nerve display when damaged?
“Peripheral” patternUlnar nerve, median nerve, etc. pattern
Dermatome
The dermis innervated by a single spinal nerve
Myotome
The muscles innervated by a single spinal nerve
Where do peripheral nerves get their blood supply?
Arterial branches
Myelinated vs unmyelinated axons
Myelinated = wrapped in myelin many timesUnmyelinated = single layer of myelin
Endoneurium
Separates individual axons
Perineurium
Surrounds bundles of axons and creates fasciclesEach fascicle is designated for a slightly different spot on the skin/muscle
Epineurium
Encloses the entire nerve trunkGathers fascicles into a nerve
Cervical plexus
C1-C4Motor, sensory, sympatheticMixes spinal into peripheral for the neck and tops of shoulders
Brachial Plexus
C5-T1Motor, sensory, sympatheticMixes spinal into peripheral for the arms
Lumbar Plexus
L1-L4Motor, sensory, sympatheticMixes spinal into peripheral for the front of the legs
Sacral Plexus
L4-S4Motor, sensory, and parasympatheticMixes spinal into peripheral for the bottom and back of legs
Name the two principles of a plexus
One peripheral nerve gets axons from many different spinal levelsOne spinal level sends axons to many different peripheral nerves
Motor damage to a peripheral nerve leads to..
Paralysis or at least major weakness in one or more muscles
Motor damage to a spinal nerve leads to..
Minor weakness in one or more muscles
Sensory damage to a peripheral nerve leads to…
Sensory loss in a “peripheral nerve” patternIncludes some, but not all, of many dermatomes
Sensory damage to a spinal nerve leads to..
Sensory loss in a “dermatomal” pattern Includes some, but not all, of many peripheral nerves
Spinal nerves are especially at risk for damage from..
Bulging intervertebral discsDeflation of an intervertebral disc
4 reasons movement is essential for nerve health
Improves blood flowFacilitates gliding of fascicles and nervesFacilitates axoplasmic transport”Wrinkling” of axons within endoneurium
The Neuromuscular Junction is only ____. Denervation here leads to ___.
ExcitatoryMuscle fibers become malnourished and waste away
Dysfunction of Peripheral Nerves leads to ___ changes (5)
SensoryAutonomicMotorFibrillationsTrophic changes
Explain the sensory changes that occur with peripheral nerve dysfunction
Location depends on if spinal or peripheralSeverity depends on if partial or complete injuryCan be anesthetic or analgesic
Explain the autonomic changes that occur with peripheral nerve dysfunction
Decreased autonomic functionIn peripheral named nerves: only sympathetic problems–skin becomes dry and red
Explain the motor changes that occur with peripheral nerve dysfunction
Location depends on if spinal or peripheralSeverity depends on if partial or complete injuryEX: peroneal N is half damaged –> anterior tibialis is weakened
Mononeuropathy
One nerve involvedEX: R handed carpal tunnel = R median N is damaged at the wrist
Multiple mononeuropathy
Involvement of two or more discrete nerves in different parts of the bodyEX: bilateral carpal tunnel = R/L median nerves damaged at the wrist
Polyneuropathy
Most common presentation is symmetrical loss of sensory, motor and autonomic function that starts distal and progresses proximal (generally feet before hands)
Name the 3 types of mononeuropathy
Traumatic myelinopathyTraumatic axonopathySeverance
Traumatic myelinopathy
Temporary disruption of conduction along axon membraneAxon remains intactDemyelination is possibleRecovery potential is excellent
Traumatic axonopathy
Axon and myelin degenerateConnective tissue “tube” remains intactWallerian degeneration occursRecovery potential very goodAxon will likely regrow into connective tissue “tube” at the rate of 1 in/month (regenerative sprouting)
Severance
Laceration (complete cut) or Avulsion (tear apart by stretching)Axon and myelin degenerateConnective tissue “tube” is severed or disruptedWallerian degeneration distal to severanceRecovery potential is fairAxons will attempt to regrow but may not find CT tube or may grow into the wrong tube
What happens if an axon doesn’t find it’s tube after severance occurs?
Sprouts can form a neuroma which is mechanically or chemically sensitive and leads to neuropathic pain
What happens if an axon finds the wrong tube after severance occurs?
The axon regrows but will not recover its function
Name 3 common etiologies of polyneuropathy
DiabetesNutritional deficitsAutoimmune disease (Guillan-Barre)
Cauda equina
Spinal nerves inside the bony spinal column below L1LMN motor axons
If the cauda equina is damaged, what happens to the stretch reflex?
Diminished because of LMN damage
Why are there cervical and lumbar enlargements?
More cell bodies and LMN for the function of the arms and legs
Medial division fibers of the dorsal root
Sensory fibersGo into the dorsal columnTouch and proprioception
Lateral division fibers of the dorsal root
Sensory axons of pain that cross the midline before going up the anterolateral column
C7 and above spinal nerves exit ___.
Above corresponding vertebrae
C8 spinal nerve exits ___.
Between C7 and T1
T1 and below spinal nerves exit ___.
Below corresponding vertebrae
White communicating rami contains ___.
Sympathetic ganglia
Gray communicating rami contains ___.
Sympathetic ganglia
Propriospinal axons
White matterInterneurons that travel between spinal segments to help coordinate multi-segment reflexes and the stepping pattern generator
Tract axons
White matterVertical column
Lateral horn
Gray matterEfferent autonomicCell bodies in preganglionic autonomic
Dorsal horn
Gray matterSensory cell bodiesPrimary synapse: pain and temperature
Lateral column
Lateral corticospinal tract (biggest in lat col)Rubrospinal tract (flexors)Motor to distal muscles
Dorsal column
Medial lemniscusLight touch Conscious proprioception
Anterolateral column
Lateral spinothalamic tractAnterior spinothalamic tractDiscriminitive painDivergent pain
Light touch sensory synapse is in the ___.
Medulla
2 Functions of the Spinal Cord
Integrate informationTransmit information
Afferent input to the spinal cord can modify ___.
The effects of descending commands
Descending commands in the spinal cord can modify ___.
The effects of afferent input
Central pattern generators
Flexible networks of interneurons that produce purposeful movement
Simple reflexes
Autogenic facilitation (muscle spindle or quick stretch reflex)-Monosynaptic-Stretch of muscle facilitates the same muscle-Takes a strong stimulus (normally)
Multisegmental reflexes
Withdrawal Reflex-Multisynaptic-Afferent pain causes muscle contraction at multiple joints/muscles-Takes a strong stimulus (normally)
Reciprocal inhibition
When an agonist is facilitated, antagonists are inhibited-Facilitate alpha motor neurons on one side and inhibit them on the other
Reciprocal inhibition occurs with ___.
Voluntary movementReflex
T/F: Reciprocal inhibition can be suppressed
True
What is the reflex stimulus and response for the bladder reflex?
Stimulus: stretch of bladderResponse: contraction of bladder (empties)
Descending parasympathetic control of the bladder reflex results in ___.
Facilitation of the voiding reflex
Descending sympathetic control of the bladder reflex results in ___.
Inhibition of the voiding reflex
Descending voluntary control of the bladder reflex is ___.
Very limited
When the bladder is stretched and it is “okay to go” ___.
Descending parasympathetic control is strongest and facilitates the voiding reflex
When the bladder is stretched and it is “not okay to go” ___.
Descending sympathetic control is strongest and inhibits the voiding reflex
If the spinal cord is damaged above the lumbar level, the bladder reflex is ___.
Stronger and easier to elicit”Spastic” bladder
If the cauda equine is damaged, the bladder reflex is ___.
Absent”Flaccid” bladder
Describe segmental function/dysfunction in the spinal cord
Signs and symptoms are at the level of the lesion onlyDermatomal sensory loss (no sensory can get in)Myotomal motor loss (no motor can get out)
Describe vertical tract function/dysfunction in the spinal cord
Sensory loss at all segments below lesionMotor loss at all segments below lesionAutonomic loss at all segments below lesion
Describe how motor loss occurs in vertical tract dysfunction
UMN paralysis leads to UMN hyperreflexia (stretch or cutaneous)
If only half of the spinal cord is damaged, describe how vertical tract function/dysfunction presents
Dorsal column signs are ipsilateral (touch and proprioception)Anterolateral column signs are contralateral (pain and temperature)Corticospinal signs are ipsilateral (voluntary motor function)
Describe segmental and vertical tract dysfunction in the spinal cord
Loss of segmental function at one levelLoss of vertical tract function at all levels below
Anterior cord syndrome
Lose motor, pain, and temperature
Central cord syndrome
Lose pain, temperature and proximal motor
Brown-Sequard syndrome
Lose touch and proprioception ipsilaterallyLose pain and temperature contralaterallyLose voluntary motor function ipsilaterally
Cauda Equina syndrome
LMN signs and symptoms:-Loss of reflexes (stretch and cutaneous)-Atrophy of denervation-Hypotonia/flaccidity-“Flaccid” paralysis-Fibrillations
Lesions above lumbar cord result in ___ bladder. Explain.
“Spastic” bladderSimilar to UMN damage which results in hyperreflexive smooth muscleBladder reflex still intact
Lesions of the cauda equina result in ___ bladder. Explain.
“Flaccid” bladderSimilar to LMN damage which results in hyporeflexive smooth muscleBladder reflex is not intact (reflex loop has been cut)
Traumatic SCI: Spinal Shock DefinitionAffect on reflexes initially and later on
Period of time after injury that non-damaged neurons are in shock and do not functionSpinal level and autonomic reflexes are temporarily absent and then become hyperactive (spastic)
Tetraplegia (quadriplegia)
4 limbs affectedDamage to cervical spinal cord
Paraplegia
2 legs affectedDamage below cervical spinal cord
Neurologic level
Lowest level or segment of spinal cord that still has normal motor and sensory function
How do you determine if someone has “normal” motor function?
MMT of fair in the key muscle for that spinal level
Abnormal reflexes display changes ___ the level of injury.
Below
2 plastic changes that occur with chronic spinal cord injury
HyperreflexiaEnhanced withdrawal response to cutaneous stimuli
3 mechanical changes in affected muscles with chronic spinal cord injury
AtrophyFibrosisContracture
Describe the atrophy that occurs with chronic spinal cord injury
Can be disuse or denervationDisuse if cut at a spinal levelDenervation if cut at a LMNDenervation leads to Wallerian degeneration and muscle wasting
Describe the fibrosis that occurs with chronic spinal cord injury
Muscle wastes away
Name the three most common sites of contracture with a SCI
PlantarflexorsHamstringsHip flexors
3 types of autonomic dysfunction in chronic spinal cord injury
Autonomic dysreflexia or hyperreflexiaImpaired body temperature regulationOrthostatic hypotension
Describe the autonomic dysreflexia or hyperreflexia that occurs with chronic spinal cord injury
Visceral stimulus produces an overresponseNo sympathetic control causes the flight or flight response to anything noxious
Describe the impaired body temperature regulation that occurs with chronic spinal cord injury
Especially with sympathetic control impairmentThe higher the injury, the more impairment
Describe the orthostatic hypotension that occurs with chronic spinal cord injury
NORMALLY: Sympathetic nervous system squeezes venuoles which results in squeezing the blood into the circulation to raise the BP when standingSympathetic nervous system is not working properly so cannot squeeze the venuoles
