Spinal Cord Clinical Correlation Flashcards
Upper motor neuron:
Neurons in CNS that terminate on (other neurons/effector organs) in CNS; i.e. Corticospinal tract
Upper Motor Neuron: M_ comes up w/ motor drive and motor planning (macro-management)
Information carried through the upper motor neuron down to the lower motor neuron > execution and micromanagement of the movement at the level of the (lower/upper) motor neuron
Lower motor neuron
Neurons in CNS whose axons terminate on (other neurons/effector organs)
i.e. skeletal muscle, cardiac muscle, glands, neurons in PNS
other neurons; M1; lower; effector organs
(Ascending/Descending) tracts: Corticospinal Rubrospinal Vestibulospinal Reticulospinal tract
Lower motor neuron: (dorsal/ventral) horn
Need to consider location of the tracts, where was the lesion, where was the area that was damaged? What track sit there, what part of the dorsal gray sits there?
Somatotopic organization: Do we anticipate extensors or flexors being limited? Axial muscles working?
Descending; ventral
(Lower/Upper) motor neuron directly innervates the muscle through alpha + gamma motor neurons @ the neuromuscular junction
(Mechanoreceptors/Proprioceptors) can influence the lower motor neurons (Flexor withdrawal, crossed extensor reflex)
1a fibers from the spindles and 1b fibers from the GTO
Upper motor neurons
Travels through the corticospinal tract + rubrospinal tract + vestibulospinal tract + medial (pontine) reticulospinal tract
Reticulospinal tract: there are 2 of them (Medial and Lateral)
All work together to influence lower motor neuron
Generally, Lateral (Medullary) reticulospinal tract grossly has a larger (excitatory/inhibitory) function on lower motor neuron
Lower; Proprioceptors; inhibitory;
Lower motor neuron lesion: something happened w/i (dorsal/ventral) horn:
Going to (gain/lose) muscle tone and muscle activation
Proprioceptive perspective
Reflex also gone because proprioceptors also (gain/lose) lower motor neurons to synapse
ventral; lose; lose
Lower Motor Neuron Signs
Paresis (weakness)/paralysis (complete inability) of voluntary movement
(Hypertonia/Hypotonia) - resting tone in muscles
When a muscle goes through denervation of the lower motor neuron = very flaccid structure
Typically have resting tone through (high/low) levels of lower motor signaling
Muscle (tetany/twitches):
Fibrillations/Fasciculations
Muscle contraction is a tetanic contraction
If no tetanic contraction = muscle twitching at rest
Result from muscle membrane excitability changes b/c of loss of lower motor neurons
Muscle (growth/atrophy)
Reduced/absent reflexes (Reflex: 0)- b/c we lose the lower motor neuron responsible for taking (mechanoreceptive/proprioceptive) signals from the spindles and translating into involuntary muscle stretch reflex
Growth hormonal responses need lower motor neurons
W/o growth hormonal responses the muscle is absorbed
Hypotonia; low; twitches; atrophy; proprioceptive
Upper Motor Neuron Lesion:
Cortical or spinal cord damage (We’re focusing on the spinal cord)
What has been lost?
Damage along the (gray/white) matter of the spinal cord (Descending tracts/Ascending) tracts)
Signaling from the upper motor neuron cannot get down to the lower motor neuron to execute a movement
What occurs immediately after upper motor neuron lesion?
Spinal ___
Complete paralysis of the segments of the cord because loss of the executive control
Regardless of the magnitude of the injury
Can last a few hours or a few days
white; descending tracts; shock;
Upper Motor Neuron Signs:
These symptoms are (before/after) spinal shock
Upper motor neuron signs are similar to lower motor neuron signs
Paresis/paralysis of voluntary movement
(Hypotonia/Hypertonia) - increased tone within muscle
Spasticity
(Hyporeflexia/Hyperreflexia) - (+++, 3+)
Clonus (++++, 4+) - Repetitive sequential activation of joint flexor and extensor muscles
Central inhibition controls muscle contraction
If Central inhibition is lost - reflex become (hyper/hypo)
Clonus: repetitive activation and deactivation of flexors and extensors
To test for clonus - stretch joint quickly will cause reverberating beating
Clonus due to loss of function in the cerebral inhibition circuitry and spindles go haywire
Clonus is more significant type of hyperreflexia because its impact on locomotor control
_____ sign
Dorsiflexion of great toe when plantar-lateral aspect of the foot is stroked with a blunt object - opposite reaction of what you would expect when being tickled on plantar aspect of foot
after; Hypertonia; Hyperreflexia; hyper; Babinski
Hyper-tonia: abnormal muscle tone
3 different types of hypertonia = spasticity (main focus), rigidity, and dystonia
Spasticity: velocity dependent (decrease/increase) in muscle tone
Spasticity: when joint quickly moved from flex/ext or vice verse –> will result in involuntary resistance through motion through detection of motion in the spindle fibers in the muscle. Abnormal muscle tone
Reason for spasticity: loss of inhibitory control of the (lateral/medial) reticulospinal tract
(Lateral/Medial) reticulospinal tract grossly responsible for inhibitory function on the lower motor neuron
When this is lost, muscle can become spastic to quick stretch
(Lower/Upper) motor neuron issues will result in spasticity. Does not result in rigidity or dystonia
increase; lateral; lateral; Upper
3 incomplete spinal cord injury syndrome (from most common to least common)
- (Central/Posterior) cord syndrome:
- (Anterior/Posterior) cord syndrome:
- (Anterior/Posterior) cord syndrome:
Central; Anterior; Posterior
Central cord syndrome/lesion:
(Anterior/Central) part of spinal cord is damaged, injured, impaired
Magnitude can be variable
Magnitude dependent on size of lesion, location
Tends to be traumatic, usually occurring at the (cervical/thoracic) spine, typically occurring w/ (hyperflexion/hyperextension) injuries
Can occur due to
Acceleration velocity can have a tension and pull of the spinal cord > results in disturbance of the central inner fibers
Degenerative changes across the vertebral bodies (spinal column not as smooth w/ older age) > jagged edge can snag on the spinal cord > disturb the inner matrix of the spinal cord
If there are motor deficits > UE tend to be (less/more) involved than the LE
b/c w/i the lateral corticospinal tract, the LE sits more (medially/laterally)
UE sits more centrally and (medially/laterally) w/i cord
Tendency to have more UE involvement than the LE
Central; cervical; hyperextension; more; laterally; medially;
REVIEW SLIDES OF 17-20 ON PPT
GOT IT
Spinal cord is perfused by the (anterior and posterior/medial and lateral) spinal arteries
Posterior and anterior spinal arteries come off the _____ artery
Vertebral artery travels up w/i lateral gutter of typically c_ and up (about 5-10% of population vertebral artery starts at c7)
Posterior spinal artery: gives perfusion to the (anterior/posterior) column (in blue) ( gives off perfusion to the posterior column, (anterior/lateral) corticospinal tract (LE portion w/ human variance), and the dorsal/posterior grey matter/horn)
Anterior spinal artery: gives off perfusion to the (UE/LE) lateral corticospinal tracts, anterolateral system, anterior and medial white matter (all postural tracts, anterior white commissure), and anterior/ventral gray matter (lower motor neuron)
Things that can put pressure on anterior/posterior spinal artery
Herniation of the nucleus pulposus > may not be the magnitude of directly compressing the cord but can pinch off parts of the anterior spinal artery (luckily, posterior spinal artery can also provide supplementary blood flow to areas in the anterior side but will not be able to reach the anterior gray)
Zygapophyseal joints bony growth > can shut off blood supply and infringe upon space
anterior and posterior; vertebral; C6; posterior; lateral; UE;
_____: Ischemic spinal cord injuries
Damage that happens as a result of medical intervention (ex. epidural injections)
Most common injection into the epidural space are _____steroids
Corticosteroids tend to clump together at the molecular level
There are 2 different types of steroidal medication:
1. particulate betamethasone
Clumps together and can form steroid blobs (micrometer)
When injected into epidural space and have a steroid that clumps together > can aggregate and clump together to form a larger steroidal blob
Nerve and arterial supply are very close to each other. IF injection misses the nerve and injects into artery > can block the arterial or capillary levels > resulting in spinal cord ischemia (profusion becomes limited because of the clumping of the steroidal molecules)
2. Non particulate: Dexamethasone (typically used for inflammatory control)
Doesn’t clump together
iatrogenic; cortico;
Syringomyelia
Fluid filled cyst (cyrinx) that forms around central canal
Tumor
Spinal trauma
Chiari Malformation: brain tissue pressure of spinal canal
Idiopathic
(LOWLY/HIGHLY) variable symptoms because dependent on size of the lesion
Can occur if something is blocking the ____ flow w/i the central canal > ____ starts to back up and forms a bubble > as bubble grows, damage the surrounding structures b/c the syrinx starts to push against the soft tooth paste textured spinal cord
HIGHLY; CSF; CSF
Typically, the cerebellum is tucked away neatly inside the cranial vault
In Chiari malformation: have a herniation of the bottom most aspect of the (cerebrum/cerebellum) into the foramen magnum > puts pressure on the spinal cord > causes a potential backup of fluid somewhere down the level of a cord > can POTENTIALLY lead to a syrinx
Not all Syrinx comes from a chiari malformation
To resolve:
perform a craniotomy of the (frontal/occipital) lobe to relieve pressure
cerebellum; occipital
Syringomyelia
HIGHLY variable symptoms
Early lesion: (SMALL RED CIRCLE IN THE MIDDLE)
Loss of (Anterior/Posterior) white commissure
Anterior Lateral system (ALS)
(Unilateral/Bilateral) loss of pain, temperature and crude touch @ level of lesion
Some motor neurons lost in (dorsal/ventral) horn
Paresis of axial musculature and proximal flexor & extensor musculature
Anterior; bilateral; ventral
Syringomyelia
Late lesion: (BIG RED CIRCLE IN THE MIDDLE)
Early lesion symptoms persist
Can involve upper motor neuron signs, lower motor neuron signs, autonomic nervous system
As the lesion grows (less/more) fluid begins to back up as time goes on
more
Ipsilateral Segmental Motor Syndrome
Poliomyelitis (polio) Affects certain (LMNs/UPNs)
Lower motor neuron signs Paresis/paralysis Hypotonia Hyporeflexia/areflexia Fasciculations
Polio is a type of ipsilateral segmental motor syndrome = impacts the (same/contralateral) side of where the lesion is.
Its segmental, can happen at just one level or multiple levels
Involved the (dorsal/sensory / ventral/motor) horn
No longer a thing because of the salk vaccine
If disease is on the left side > only going to impact the lower motor neurons on the (left/right) side
Polio epidemic got PT entrenched the need to have individuals that can rehabilitate motor control issues
LMNs; same; ventral/motor; left;
Ipsilateral Segmental Motor Syndrome
Poliomyelitis - Post polio syndrome
Remaining LMNs
(Enlarge/Minimize) to cover the muscle fibers that were denervated by the virus
Allows for some degree of recovery
2° aging process - the giant LMNs will die off and function (improves/declines)
Doesn’t take out all of the motor neuron pool, just takes out some of them
Green ones are remaining:
b/c of neuroplasticity these 3 lower motor neurons are still intact start growing collateral buds
Takes over some of the loss function of their neighbors that had been lost due to polio
The motor neuron starts to get larger b/c they are taking over the role of the lost motor neuron > do get some level of recovery of function
Unfortunate things about the lower motor neurons enlarging to take over some muscle capacity for lost motor neurons is that the enlarge lower motor neurons die off because of overuse > begins to see same symptoms return again = Post polio syndrome
Enlarge; declines
Brown-Sequard syndrome
Hemi section of the cord b/c vertebral body fracturing pushes onto 1.5 of the cord
Stabbings, gunshot wounds can also result in hemi section of the cord
Spinal cord hemisection
(1-2/3-4) segments
Ipsilateral findings
Loss of conscious proprioception, kinesthesia & discriminative touch
(Below/above) level of injury b/c loss of DCML
UMN signs
(Below/above) level of injury b/c loss of lateral corticospinal tract, anterior corticospinal tract, rubrospinal tract
LMN signs
(At level of injury/below level of injury)
Autonomic signs
Intermediolateral cell column if happens w/i (cervical/thoracic) body
Contralateral findings:
Loss of pain & temperature
(Above/Below) level of injury
b/c where the fiber decussates
Bilateral findings
Loss of pain & temperature
(Below level of injury/At level of injury)
b/c loss of dorsal columns
Lost ipsilateral pain and temperature
Also lost anterior commissure
So information from the left side also lost
1-2; below; below; at level of injury; thoracic; below; at level of injury;
