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SCI Flashcards

1
Q

How far down does the spinal cord travel down the vertebral column?

A

L1/L2

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2
Q

Fiber bundles that have same course and same terminations

A

Fascicule (tracts)

-tend to have the same functions

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3
Q

Where are the descending tracts located in the SC? ascending?

A

Descending: lateral and ventral
Ascending: posterior, anterior, and lateral

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4
Q

Where is the medial reticulospinal tract? lateral?

A

Medial AKA pontine reticulospinal tract = pons

Lateral AKA medullary retuculospinal tract= medulla

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5
Q

What is in gray matter?

A
  1. Cell bodies
  2. Dendrites
  3. Myelinated and unmyelinated axons
  4. Glial cells
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6
Q

What laminal layer is dorsal horn? intermediate zone? Ventral horn? around central canal?

A
  • Dorsal horn: Laminae I – VI
  • Intermediate zone: Lamina VII
  • Ventral horn: Laminae VII – IX
  • Area surrounding central canal: Lamina X
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7
Q

What motor neurons are located in the medial ventral horn?

A

Proximal muscles

  • proximal flexors are dorsal
  • proximal extensors are ventral
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8
Q

What motor neurons are located in the lateral ventral horn?

A

Distal muscles

  • proximal flexors are dorsal
  • proximal extensors are ventral
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9
Q

Injury to structures that are involved at that level of the injury

A

Segmental injuries

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10
Q

What are the being injured in segmental injuries?

A

Dorsal or ventral roots

Dorsal or ventral horn

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11
Q

Injury to structures that are passing through the level of the injury to or from more caudal structures

A

Vertical tract injury

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12
Q

What are being damaged in vertical tract injuries (or white matter)? Where will signs and symptoms be seen?

A

UMN pathways or ascending sensory tracts (ascending and descending axons)
- impairments seen below level of injury

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13
Q

What are being damaged in segmental injuries (or gray matter? Where will signs and symptoms be seen?

A

Sensory internuerons in DH, 2nd neuron in the spinothalamic pathway, and Damaging LMN
- S and S at level of injury

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14
Q

What are S and S of SC lesions?

A
  1. Pain
  2. Paresthesias and numbness
  3. Muscle weakness
  4. Abnormal somatic reflexes and muscle tone
  5. Autonomic dysfunctions
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15
Q

From damage to bony and ligamentous structures surrounding the cord; Can develop rapidly (trauma, infarction, herniation) or slowly (tumor, transverse myelitis, syringomyelia); More severe over vertebral column at level of lesion but may spread to more distal areas

A

Local pain

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16
Q

Damage to sensory nerve roots; Pain may be excruciating; May be associated with local pain; Dermatomal pattern

A

Radicular pain

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17
Q

Occasionally seen; Due to dysfunction in spinal cord pain pathways; Usually in patients with traumatic SCI (can develop months after injury); Not localized to level of lesion (Can be at or below level of lesion)

A

Diffuse Aching or Burning pain

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18
Q

What causes paresthesias?

A

Abnormal activity in dorsal roots and DC pathways

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19
Q

What sensory abnormality occurs as a result to damage to dorsal column? ALS?

A

Numbness or deadness; analgesia

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20
Q

What UMNs are damaged that lead to weakness? where are the injured LMN located?

A

UMN - Lateral corticospinals in lateral column

LMN - in ventral horn and root

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21
Q

Occurs due to extensive spinal cord lesions (due to trauma, infarction, hemorrhage, transverse myelitis); Transient state of markedly depressed spinal cord activity; Usually resolves within several weeks, and have an evolving state of hyperreflexia and spasticity

A

Spinal shock

- both somatic and visceral areflexia occur

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22
Q

When the bladder becomes full, _____ receptors in the bladder wall are activated. Afferent information goes to the reflex center in the sacral cord. Parasympathetic fibers produce contraction of ____ and open ______. ________ open the external sphincter.

A

stretch; bladder wall; internal sphincter; Somatic fibers (S2-S4)

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23
Q

What is required for reflexive bladder control?

A
  • does not involve conscious control*
    1. Sensory afferents
    2. T11 to L2 and S2-S4 spinal cord levels
    3. Somatic, sympathetic and parasympathetic efferents
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24
Q

SCI that results in: Sensory and motor tracts in SC are disrupted; Sensory and motor function severely disrupted below level of lesion; Sensory systems: Radicular pain, Local vertebral pain, Segmental paresthesias

A

Complete lesions

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25
Q

What do descending corticospinal tracts terminate on?

A
  • Alpha and gamma motor neurons

- interneurons

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26
Q

Tract receives input from cerebral cortex and cerebellum; control of muscle tone, particularly in contralateral upper extremity flexors; May serve some function after injury to LatCS

A

Rubrospinal tract

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27
Q

Tract controls head, shoulder and upper trunk movements; Orientation movements of the head and neck to visual and possibly auditory input

A

Tectospinal tract

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28
Q

Tract excites extensors motor neurons; Inhibits flexor motor neurons; Acts at many levels

A

Lateral vestibulospinal tract

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29
Q

Tract influences neck and upper back muscles; Controls head position

A

Medial vestibulospinal tract

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30
Q

Tract enhances postural and extensor muscle tone

A

Pontine (medial) reticulospinal tract

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31
Q

Tract that, in general, facilitates flexors and inhibits extensors, though the actions may be reversed under some conditions; Regulates voluntary movements, reflex activities, and muscle tone

A

Medullary (lateral) reticulospinal tract

32
Q

Why do we care about sensation in a motor control class?

A
  1. Needed for smooth, coordinated and movements
  2. Protection from injury
  3. Understanding our environment (perception)
33
Q

What type of axon fibers are the DCML tract?

A

A beta (large myelinated)

34
Q

More distal regions on the body are more [medial/lateral] in the dorsal columns.

A

medial

35
Q

What are the regions of gray matter?

A
  1. Dorsal horn
  2. Ventral Horn
  3. Intermediate zone
  4. Intermediate horn (thoracic and upper lumbar levels)
36
Q

What is an early sign of UMN disease?

A

Babinski’s sign

37
Q

What does the sympathetic NS innervate? Parasympathetic? Somatic?

A 
Sympathetic = internal wall and internal sphincter
Parasympathetic = internal and external sphincter, and internal wall
Somatic = external sphincter
38
Q

What do sympathetic fibers from T11-L2 do?

A
  1. Inhibit contraction of bladder wall

2. Maintain contraction of internal sphincter

39
Q

A bladder under voluntary control has sensory info sent from reflex center in the SC to the brain. What happens if the decision is made for micturition?

A
  1. Corticospinal inhibition of external sphincter muscle

2. Brainstem pathways to autonomic efferents

40
Q

Bowel and bladder control are very similar. What is the stimulus for bowels?

A

Stretch of recutm

41
Q

What fibers are needed for erection? what fibers are needed for ejaculation?

A 
Erection = parasympathetic fibers from S2-S4
Ejaculation = Sympathetic fibers from L1,L2; pudendal nerve from S2-4, as somatic efferents
42
Q

What do lateral corticospinal tracts control in terms of visceral function? lateral columns?

A

lat corticospinals = volitional control of breathing

lat columns = volitional control of micturition, automatic control of micturition, breathing sweating, BP

43
Q

What bladder dysfunction occurs with spinal shock? lesion of caudal equina or S2-4? lesion above T11?

A

Areflexic bladder (loss of uniration reflex); areflexic bladder continues; hyperreflexic/ spastic bladder (UMN injury: Loss of conscious awareness of bladder, Bladder capacity is decreased, Increased bladder pressure (due to lost control of sphincter), Incomplete emptying, Urine retention)

44
Q

People with urinary dysfunction have a higher risk of:

A
  1. UTI
  2. Urinary stone formation
  3. Upper urinary tract degeneration
45
Q

What are causes of SCI that commonly produce urinary dysfunction?

A
  1. SCI
  2. MS
  3. Tumors
  4. Tabes dorsalis due to syphilis (damage to dorsal columns)
46
Q

As far as genital dysfunction, what is seen in a lesion above T12?

A
  1. Psychogenic erections abolished
  2. Reflexive erections may persist in LMN intact
  3. Ejaculation occurs in only a small proportion of patients with significant spinal cord injury (if children are wanted, sperm samples are taken and frozen; As time goes by, quality of sperm production decreases)
  4. Women can become pregnant and carry baby to term (birth is usually by C-section)
47
Q

What spinal levels are the main muscles of breathing? accessory muscles?

A
  • Main muscles:
    1. Diaphragm: C3-C5
    2. Intercostal: T1-T12 - Assist with normal inspiration, High volume expiration
    3. Abdominal muscles: T6-T12- Assist with expiration
  • Accessory muscles:
    1. Sternocleidomastoid: C1-C3
    2. Scalenes: C4-C8
    3. Trapezius: C1-C4, CN XI
48
Q

What are the effects of SCI on breathing in the following levels:
Lumbar, thoracic, lower cervical, C4-C5, C3 or higher

A
  1. Lumbar – little effect
  2. Thoracic - Impair cough, little effect on normal breathing
  3. Lower cervical - More effects on breathing
  4. C5 or higher - Affect diaphragm
  5. C3 or higher -Bilateral diaphragm paralysis, Require artificial ventilation
49
Q

In terms of breathing, what would a lesion to corticospinal tracts do?

A

voluntary breathing will be blocked, but automatic breathing can remain intact

50
Q

What region of the spinal cord is automatic breathing carried?

A

Anterolateral white matter

51
Q

What autonomic dysfunctions are seen in complete SCIs?

A
  1. Spastic bladder
  2. Bowel constipation
  3. Anhidrosis – decreased sweating
  4. Trophic skin changes - outer gets thinner, subcutaneous gets thicker - difficulty keeping out infections
  5. Impaired temperature control
  6. Vasomotor instability - BP control loss (may increase or decrease)
52
Q

What tracts are damaged in anterior cord syndrome? What can cause this?

A
  • anterior ⅔rd spinal cord
    1. anterior horn (LMN)
    2. spinothalamic tract
    3. lateral corticospinal tract
    Causes:
    1. Ischemia (anterior spinal artery)
    2. Infarction
    3. Trauma- Flexion type injury, Acute traumatic disk herniation
53
Q

What tracts are damaged in posterior cord syndrome?

A

DCML

54
Q

What tracts are damaged in posterolateral cord syndrome? What can cause this?

A
  1. DCML
  2. Lateral corticospinal
    Causes:
  3. Subacute combined degeneration of SC: Severe vitamin B12 deficiency, AIDS, or Pernicious anemia
  4. Chronic syphilis – Dorsal column syndrome
55
Q

What tracts are damaged in central cord syndrome?

A
  • Segmental injury
  • UE motor more involved than LE, bc corticospinal fibers are more medial and injury is often cervical cord
    1. spinothalamic tract at crossing point
    2. possible damage to ventral horn, depending on how large lesion is
56
Q

What type of SCI causes the following S and S:

  • Parathesias in feet
  • Impaired vibration sense and proprioception in legs resulting in sensory ataxia
  • Motor dysfunction: Spastic weakness, Hyperreflexia, Babinski’s signs
  • Pain and temperature sensation intact
A

Posterolateral cord syndrome

57
Q

What type of SCI causes the following S and S:

  • Losses below level of lesion = Motor control, Pain and temperature sensation
  • Intact sensations: Discriminative touch, Vibration sense, Proprioception
A

Anterior cord syndrome

58
Q

What type of SCI causes the following S and S:

  • Loss of fine touch, proprioception, and vibration sense
  • Marked sensory ataxia causes by loss of proprioceptive pathways
A

posterior cord syndrome

59
Q

What can cause central cord syndrome?

A
  1. Severe hyperextension injury of neck
  2. Tumor
  3. Postradiation myelopathy
  4. Infarction
  5. Syringomyelia - caused by trauma or can just happen
60
Q

What are the causes of Brown-Sequard syndrome?

A
  1. Multiple sclerosis
  2. Tumor
  3. Syringomyelia - starts at central canal and moves to one side
  4. Penetrating wound of spinal cord
61
Q

S and S include:

  • Weakness and numbness of feet (less often the hands and arms)
  • Difficulty in emptying the bladder
  • Develop over several days
  • Symptoms usually remain stable, and then slowly improve
A

Transverse myelitis

62
Q

What can cause SCI due to vascular disorders?

A
  1. Arterial obstruction or hemorrhage
  2. Dissecting arterial aneurysm
    Complication of vascular surgery
  3. Vascular malformations (Arteriovenous malformations)
  4. Injury by general hypoxia/ischemia or hypotension (cardiac arrest or hemorrhage)
63
Q

usual S and S include:
Sensorimotor spinal tract symptoms – compression
- Asymmetric spastic
- Impaired pain and thermal sensation
- weakness
- Dorsal column signs – paresthesias
- Loss of voluntary bowel and bladder control

Radicular-spinal cord syndrome – includes radicular pain

A

Tumors

- most common is extradural metastasis (from lung, breast, prostate)

64
Q

Where are most SCIs due to trauma?

A
  1. Cervical spine

2. Thoracolumbar junction

65
Q

What is the difference between direct and indirect injuries?

A

Direct happen directly to the SC, where indirect occurs to vertebral column which then injures the SC (more common)

66
Q

What is necrotic tissue replaced by with long therm changes in SCI?

A
  1. Scar tissue

2. Cysts or cavities

67
Q

What is the difference between a direct and indirect mechanism for SCI?

A

Direct = injury directly to SC (stab wound)

Indirect - injury to vertebral column, which then damages spinal cord (fracture, more common)

68
Q

Where is the spinal canal largest? why does this matter?

where is it the smallest in the cervical region?

A

C1/2 level - allows more room so damage doesn’t occur to SC (75% pts with c1/2 fc have no neurological damage)
between C4 and C6

69
Q

What are lower cervical cord or nerve root injuries usually due to?

A
  1. compression from: (Vertebral body fracture, Disc herniation)
  2. Stretching due to excessive movement between vertebrae
70
Q

What forces cause cervical cord injury?

A
  1. Flexion (Auto accident, Most consistently results in neurological damage)
  2. Vertical compression (Injury most often at C4-5)
  3. Hyperextension
71
Q

In the thoracic spine, SCI are less common but more likely to be complete bc the spinal canal is narrowest in this region. What injuries can cause a SCI in the thoracic region?

A
  1. Vulnerable to compression and flexion injury
  2. Also more vulnerable to vascular injury (Artery of adamkiewicz – if this is damaged, there are several damaged; usually due to dissecting anneurism)
72
Q

Why does a cauda equina injury result in less severe injuries?

A
  • only damaging LMN
  • spinal canal widens btwn T11 and L2
  • good vascular supply
  • more likely to happen in a thoracolumbar SCI
73
Q

What are the mechanisms of secondary injury?

A
  1. Hemorrhage
  2. Ischemia
  3. Local electrolyte derangements
  4. Inflammatory reactions (glucocorticoids)
  5. Local accumulation of various bioreactive substances
74
Q

What causes orthostatic hypotension? what causes autonomic dysreflexia

A
  • loss of sympathetic vasoconstricition

- over activation of sympathetic NS (SCI T6 and up)

75
Q

What type of sweating is seen in SCI?

A
  • Reflexive sweating may be intact
  • Thermoregulative sweating impaired below level of injury – body temp goes up, so body is stimulated to start sweating
  • May have compensatory excessive sweating above the level of the injury

Neuroscience (19 decks)

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