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Neuroanatomy (OCCU 6140) > Midterm 4 > Flashcards

Midterm 4 Flashcards

Peripheral nervous system injury & repair Spinal cord and brainstem lesion

1
Q

Neurons in the cerebral cortex and brainstem that govern the activity of lower motor neurons in the brainstem and spinal cord

A

Upper motor neurons

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2
Q

Alpha motor neurons innervate intrafusal muscle fibers for muscle contraction, true or false?

A

False, alpha motor neurons innervate extrafusal muscle fibers for muscle contraction

Alpha motor neurons = extrafusal

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3
Q

Gamma motor neurons innervates intrafusal muscle fibers (muscle spindles), true or false?

A

True

Gamma motor neurons = intrafusal

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4
Q

Innervate extrafusal muscle fibers for muscle contraction

A

Alpha motor neurons

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5
Q

Innervate intrafusal muscle fibers (muscle spindles)

A

Gamma motor neurons

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6
Q

Somatic motor lower motor neurons are alpha motor neurons, true or false?

A

True

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7
Q

The cell body of somatic motor neurons is located where?

A

Anterior/ventral horn

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8
Q

Cervical and lumbosacral enlargements in the spinal cord are to accommodate for…

A

Extra motor units for the limbs

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9
Q

Axons of the somatic motor neurons in the spinal cord form the _________________ root.

A

anterior/ventral root

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10
Q

Axons of the somatic lower motor neurons join posterior/dorsal sensory roots to form the ___________________ for each spinal level.

A

Spinal nerve

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11
Q

Cranial nerve lower motor neurons originate in the ________________.

A

Brainstem

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12
Q

The alpha motor neuron and the skeletal muscle fibers it innervates together form the ___________________.

A

Motor unit

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13
Q

Spinal nerves are made up of posterior (sensory) roots and anterior (motor) roots. Spinal nerves split to become posterior and anterior ________________. Anterior ________________ at various levels combine to become trunks of the brachial and lumbosacral plexi. Ultimately, separate to terminal branches called _______________________.

A

Rami
Peripheral nerves

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14
Q

Efferent =
Afferent =

A

Efferent = motor
Afferent = sensory

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15
Q

A _______________ is an area of skin that is mainly supplied by afferent nerve fibers from the dorsal root of a spinal nerve.

A

dermatome

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16
Q

Clinically, there is overlap between the dermatomes, the borders are not as distinct as it seems in textbooks, true or fale?

A

True

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17
Q

Terminal branches of the peripheral nervous system are called…

A

Peripheral nerves

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18
Q

Peripheral nerves are a collection of axons surrounded by _________________.

A

connective tissue layers

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19
Q

Peripheral nerves are mixed (motor and sensory), true or false?

A

True

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20
Q

Cranial nerves are not peripheral nerves, true or false?

A

False, cranial nerves are peripheral nerves

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21
Q

Damage to the descending tract BEFORE the anterior horn of the spinal cord is referred to as:

A

Upper motor neuron syndrome

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22
Q

Damage to alpha motor neuron at or distal to the anterior horn is referred to as:

A

Lower motor neuron syndrome

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23
Q

Upper motor neuron lesions refer to damage where?

A

Before/proximal to the anterior horn

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24
Q

Lower motor neuron lesions refer to damage where?

A

At or after/distal to the anterior horn

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25
Q

With a lower motor neuron lesion, would you expect to see weakness/paralysis/paresis?

A

Yes, flaccid paralysis

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26
Q

With an upper motor neuron lesion, would you expect to see weakness/paralysis/paresis?

A

Yes, spastic paresis and spastic weakness

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27
Q

What type of lesion would produce spastic weakness ipsilateral and below the lesion?

A

Upper motor neuron lesion

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28
Q

What type of lesion would produce flaccid paralysis ipsilateral and at level of the lesion

A

Lower motor neuron lesion

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29
Q

What type of lesion would produce spastic paresis contralateral and below lesion?

A

Upper motor neuron lesion

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30
Q

With a lower motor neuron lesion, would you expect to see hypotonia?

A

Yes, loss of tone is often present in a LMN lesion

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31
Q

With a lower motor neuron lesion, would you expect to see hypertonia?

A

No, increased tone is not present in a LMN lesion (hypotonia is present)

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32
Q

With an upper motor neuron lesion, would you expect to see hypertonia?

A

Yes, hypertonia (increased tone) is often present in an UMN lesion

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33
Q

With a lower motor neuron lesion, would you expect to see hyporeflexia?

A

Yes, hyporeflexia (decreased reflexes) is often present in a LMN lesion

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34
Q

With an upper motor neuron lesion, would you expect to see hyporeflexia?

A

No, hyporeflexia (decreased reflexes) is not present in an UMN lesion, hyperreflexia (increased reflexes) is present

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35
Q

With a lower motor neuron lesion, would you expect to see hyperreflexia?

A

No, hyperreflexia (increased reflexes) is not present in a LMN lesion; HOWEVER, there is an exception: it may be seen due to facilitated nerve root

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36
Q

With an upper motor neuron lesion, would you expect to see hyperreflexia?

A

Yes, hyperreflexia (increased reflexes) is often present in an UMN lesion

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37
Q

With an upper motor neuron lesion, would you expect to see a positive Babinski and Hoffman’s sign?

A

Yes

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38
Q

With a lower motor neuron lesion, would you expect to see a positive Babinski and Hoffman’s sign?

A

No

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39
Q

With an upper motor neuron lesion, would you expect to see atrophy?

A

None, or minimal

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40
Q

With a lower motor neuron lesion, would you expect to see atrophy?

A

Yes

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41
Q

When performing nerve conduction tests, in the case of an upper motor neuron lesion, would the results be normal or abnormal?

A

Normal

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42
Q

When performing nerve conduction tests, in the case of a lower motor neuron lesion, would the results be normal or abnormal?

A

Abnormal

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43
Q

When performing EMG, in the case of an upper motor neuron lesion, would the outcome be normal or abnormal?

A

Normal

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44
Q

When performing EMG, in the case of a lower motor neuron lesion, would the outcome be normal or abnormal?

A

You would see fibrillation potentials

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45
Q

With an upper motor neuron lesion, would you expect to see fasciculations?

A

No

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46
Q

With a lower motor neuron lesion, would you expect to see fasciculations?

A

Yes

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47
Q

There isn’t much overlap between upper motor neurons and lower motor neurons in the spinal cord, true or false?

A

False, there is a lot of overlap between upper motor neurons and lower motor neurons in the spinal cord.

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48
Q

In the case of an upper motor nerve injury involving a stroke, what might you expect to see as a result?

A

Paresis
Positive Babinski and Hoffman’s
Hyperreflexia
Hypertonia

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49
Q

In the case of an upper motor nerve injury relating to a spinal cord injury, what might you expect to see as a result?

A

Weakness below level of lesion (often bilateral)
Hypertonia (increased tone)
Hyperreflexia (increased reflexes)
Sensory loss below the level of lesion
Bladder and bowel involvement

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50
Q

Amyotrophic lateral sclerosis (ALS) involves both upper motor neurons and lower motor neurons, true or false?

A

True

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51
Q

The symptoms of amyotrophic lateral sclerosis (ALS) are caused (simple terms) by…

A

A decrease in the number of motor units

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52
Q

Name some symptoms of amyotrophic lateral sclerosis (ALS)

A

Muscle weakness and wasting
Fatigue
Fasciculations
Negative prognosis (death)

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53
Q

Name the most prominent (common) signs and symptoms of a alpha motor neuron injury

A

Lower motor neuron syndrome
Wasting and weakness (diffuse)
Hyporeflexia
Hypotonia
Fasciculations
No sensory involvement

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54
Q

In lower motor neuron syndrome, there is expected sensory involvement, true or false?

A

False, there is no sensory involvement

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55
Q

Explain the signs and symptoms of a spinal nerve injury

A

Weakness in distribution of nerve root (myotome weakness)

Associated sensory symptoms in same distribution (dermatome)

Pain along sensory distribution

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56
Q

Explain the signs and symptoms of a peripheral nerve injury

A

Weakness and sensory loss in distribution of affected nerve(s) (e.g., radial nerve)

Wasting if severe

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57
Q

Clinically, how do we differentiate between a spinal and peripheral nerve injury?

A

Difficult ?????

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58
Q

What is Guillain-Barre Syndrome?

A

Immune-mediated peripheral neuropathy
(preceded by acute infectious illness in 2/3 of patients)

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59
Q

Explain in simple terms the cause of Guillain-Barre Syndrome

A

Destruction of the myelin sheath with axonal damage

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60
Q

Explain in simple terms the cause and effects of Guillain-Barre Syndrome

A

Rapidly progressing motor and sensory impairments caused by destruction of myelin sheath with axonal damage

Loss of deep tendon reflexes

Varying degrees of severity:
Mild (ambulation difficulty)
Severe (requiring ventilation)

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61
Q

Guillain-Barre Syndrome affects the central nervous system, true or false?

A

False, it affects the peripheral nervous system

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62
Q

Peripheral nerve injuries can be classified, explain the following classifications:
- Neuropraxia
- Axonotmesis
- Neurotmesis

A

Neuropraxia: focal myelin injury, axon intact

Axonotmesis: injury to axon and myelin but supporting connective tissue is intact

Neurotmesis: complete nerve laceration, injury to axon and supporting connective tissue

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63
Q

Explain neuropraxia

A

Neuropraxia is a peripheral nerve injury classification.

It involves focal myelin injury, temporary conduction block, transient weakness and/or paresthesia and the axon remains intact.

64
Q

Explain axonotmesis

A

Axonotmesis is a peripheral nerve injury classification.

It involves injury to the axon and myelin, but not supporting connective tissue (remains intact).

Conduction block, denervation.

65
Q

Explain neurotmesis

A

Neurotmesis is a peripheral nerve injury classification.

Complete nerve laceration.

Injury to axon and supporting connective tissue.

66
Q

Wallerian degeneration results when…

A

A nerve fiber is cut of crushed (axonotmesis or neurotmesis) and part of the distal axon degenerates.

67
Q

A nerve fiber is cut or crushed (axonotmesis or neurotmesis) and part of the distal axon degenerates

A

Wallerian degeneration

68
Q

What are some of the ways we assess the peripheral nervous system?

A

Muscle strength
Deep tendon reflexes
Sensation testing
Nerve specific testing (Tinel’s sign)
Nerve conduction test (NCS) & electromyography

69
Q

When a peripheral nerve fiber is cut or crushed what type of nerve injury classification does this fall into?

A

Axonotmesis or neurotmesis (in neuropraxia the axon remains intact)

70
Q

Nerve conduction studies assess…

A

The integrity of the nerve (motor or sensory) and the neuromuscular junction

71
Q

In nerve conduction studies, axons are stimulated for muscle contraction, the muscle contraction is then recorded as a compound motor action potential (CMAP or M-wave).

Explain the amplitude, latency, and conduction velocity of this wave.

A

Amplitude = number of axons being stimulated

Latency = time between stimulation and M-wave, most affected by demyelination

Conduction velocity = distance/time, affected by both axonal loss and demyelination

72
Q

To determine the number of axons being stimulated when performing nerve conduction studies, which aspect of the M-wave would we look at?

A

The amplitude of the M-wave = number of axons being stimulated

73
Q

To determine the level of demyelination when performing nerve conduction studies, which aspect(s) of the M-wave would we look at?

A

The latency (time between stimulation and the M-wave) = affected by demyelination

AND

Conduction velocity (distance/time) = affected by both axonal loss and demyelination

74
Q

To determine the level of axonal loss when performing nerve conduction studies, which aspect(s) of the M-wave would we look at?

A

Conduction velocity (distance/time) = affected by both axonal loss and demyelination

75
Q

Nerve conduction studies show abnormal motor responses if they are present, axonal loss may present in a _______________ of the M-wave

A

lower amplitude

76
Q

Nerve conduction studies show abnormal motor responses if they are present, demyelination may present how?

A

The M-wave is “spread” because only some neurons are affected.

Prolonged latency (time between stimulation and M-wave)

Slow conduction velocity (time/distance)

77
Q

When conducting a nerve conduction study, you may see that the M-wave is “spread”, a prolonged latency (time between stimulation and M-wave) and slow conduction velocity (time/distance) in which case(s)?

A

Demyelination (demyelinating neuropathies)

78
Q

When conducting a nerve conduction study, you may see lower amplitude of the M-wave in which case(s)?

A

Axonal loss (peripheral neuropathy or motor neuron disease (e.g., ALS))

79
Q

Recording electrical activity from individual muscle fibers at rest and during contraction via needle electromyography allows for determination of the ‘motor unit potential’, what is this potential?

A

Summation of electrical activity of the muscle fibers in the motor unit

80
Q

Needle electromyography can be used to distinguish between ___________ , ___________ and ____________.

A

upper motor neuron lesions, lower motor neuron lesions and myopathies.

81
Q

What are the two types of peripheral nerve recovery?

A

Axonal repair and regrowth

Collateral sprouting

82
Q

The peripheral nervous system has capacity for axonal regeneration/repair, regeneration is faster closer to _________________ and slower _______________________(where?)

A

Regeneration is faster closer to the injury site and slower further away from the site of the injury

83
Q

The peripheral nervous system has capacity for axonal regeneration/repair, regrowth of the axon results in…

A

reinnervation of the target muscle

84
Q

What are the two key players in axonal regrowth?

A

Macrophages

Schwann cells

85
Q

What are the two key players in axonal regrowth and what are their roles?

A

Macrophages = clear away degenerating parts

Schwann cells = act as a guide to stimulate regrowth

86
Q

How do Schwann cells support axonal regrowth?

A

Growth cone extends to search for target

Secrete neurotrophic signals that promote axon growth

Provide a framework to help guide growing axons (tropic)
(cell adhesion molecules guide the axon to the target)

87
Q

Trophic =
Tropic =

A

Trophic = growth
Tropic = moving toward

88
Q

Crush injuries always result in Wallerian degeneration, true or false?

A

False

89
Q

The three types of peripheral nerve injuries fall into these three categories, name them:
1. Focal demyelination
2. Nerve crush
3. Nerve laceration

A
  1. Neuropraxia
  2. Axonotmesis
  3. Neurotmesis
90
Q

In a nerve crush injury, axons may have continuity and may not degenerate, true or false? Explain why

A

True, Schwann cell framework is less disrupted (than say a laceration), the damages segments distal to the crush help guide the regenerating proximal segments

91
Q

Recovery is often more rapid (and complete) in nerve cut injuries than nerve crush injuries, true or false?

A

False, recovery is often more rapid (and complete) in nerve crush injuries than nerve cut injuries

92
Q

Which type of injury is more likely to not degenerate and have less disruption of Schwann cell framework for the guidance of regeneration of proximal nerve segments, axonotmesis or neurotmesis?

A

Axonotmesis (nerve crush injury)

93
Q

Severed nerves are reconnected using _________________ surgery.

A

Re-apposition surgery

94
Q

Transected nerves are salvageable if repaired within _____________months.

A

3 months

95
Q

Even with extensive damage, new Schwann cells can regrow, true or false?

A

True

96
Q

If there is a severe nerve injury and the distal end is not available for re-apposition, outcomes tend to be poor, true or false?

A

True, less than 50% of patients recover satisfactory motor and sensory function after nerve repair

97
Q

Henry Head (British Neurologist) completed a nerve regrowth experiment in 1903, what did he do?

A

He surgically transected his own radial nerve and had his colleague surgically repair it (re-apposition)

He then followed recovery by documenting the return of sensation and movement

98
Q

Reinnervation can be imprecise, training the neuron may result in plastic changes for _________________ remodeling

A

Activity-dependent

99
Q

In humans, evidence demonstrating a positive effect of exercise on nerve regeneration is at best poor, true or false?

A

True

100
Q

Intraoperative electrical stimulation may improve axonal regeneration and muscle reinnervation, true or false?

A

True

101
Q

If the peripheral nervous system is healthy, the M-wave should have a ___________ amplitude.

A

Normal amplitude

102
Q

Many diseases, and even healthy aging, can decrease the number of motor ____________ in humans.

A

Units

103
Q

What would we expect the M-wave amplitude to be in the older population?

A

The M-wave amplitude will remain preserved (relatively the same) despite a decrease in the number of motor units.

This is due to motor unit remodeling (collateral sprouting)

104
Q

Explain collateral spouting in the peripheral nervous system in simple terms

A

If you have two motor units for instance and lose one of them, the preserved motor unit sprouts new axons to reinnervate muscles fibers, and motor unit size

105
Q

Emily is a 28-year-old trans white woman presenting to the hospital with progressive muscle weakness and tingling sensations in her legs and arms that gradually progressed over the course of a few days.

Do you think she has an upper motor lesion or a lower motor lesion?

A

Lower motor neuron lesion

106
Q

Emily is a 28-year-old trans white woman presenting to the hospital with progressive muscle weakness and tingling sensations in her legs and arms that gradually progressed over the course of a few days.

What condition do you think Emily has?

A

Lower motor syndrome

107
Q

Emily is a 28-year-old trans white woman presenting to the hospital with progressive muscle weakness and tingling sensations in her legs and arms that gradually progressed over the course of a few days.

What would you expect to see on nerve conduction testing and needle EMG?

A

Nerve conduction testing: Lower amplitude, prolonged latency, slowed conduction speed

Needle EMG: Increased insertional activity, fibrillation at rest, increased activity at minimal voluntary contraction, low firing rate at maximal voluntary contraction

108
Q

In an upper motor neuron lesion what would you expect to see on needle EMG?

A

Normal insertional activity

At rest NO fibrillation

Normal minimal voluntary contraction

Low firing rate at maximal voluntary contraction

109
Q

For myopathy what would you expect to see on needle EMG?

A

Normal insertional activity

NO fibrillation at rest

Small minimal voluntary contraction

Full recruitment pattern and low amplitude at maximal voluntary contraction

110
Q

Poliomyelitis is due to a poliovirus infection, it has been largely eradicated due to immunization.

Paralytic poliomyelitis is caused by damage to ____________________ cells, resulting in muscle weakness, wasting, paralysis, and/or respiratory dysfunction.

A

Anterior horn cells

111
Q

Recovery from poliomyelitis usually occurs within 6-9 months, although some weakness persists, what is this recovery due to?

A

Motor unit collateral sprouting (fewer motor units but relatively preserved strength)

112
Q

There was an epidemic of neuromuscular and orthopedic problems in poliomyelitis survivors, why is this?

A

With normal aging there is a decrease in motor unit numbers, collateral sprouting allows muscle strength and function to be preserved.

In polio survivors, the number of motor units is already at a critically low number, therefore there is still a resulting decline in strength and function

113
Q

Loss of upper motor neuron control of lower motor neurons leads to enhanced _______________.

A

Spinal reflexes

114
Q

Upper motor neuron lesions lead to what type of paralysis?

A

Spastic paralysis

115
Q

Lower motor neuron lesions lead to what type of paralysis?

A

Flaccid

116
Q

Upper motor neuron lesions lead to increased or decreased deep tendon reflex?

A

Increased

117
Q

Lower motor neuron lesions lead to increased or decreased deep tendon reflex?

A

Absent

118
Q

Activation of lower motor neurons is regulated by a competition of ___________ and ______________ inputs.

A

excitatory and inhibitory inputs

119
Q

Loss of upper motor neurons leads not only a reduced excitation but also a reduced ______________

A

inhibition

120
Q

Loss of upper motor neurons leads not only to reduced excitation but also to reduced inhibition, this can lead to decreased tonic inhibition of lower motor neurons, therefore sensory afferents at the level of the spinal cord (reflexes) can have a _______________ influence.

A

greater

121
Q

Muscles receive trophic factors from lower motor neurons, loss of lower motor neurons therefore leads to _________________.

A

Atrophy (muscles wasting)

122
Q

Following lower motor neuron lesions muscles can become spontaneously active, producing _______________________ or, when damage is severe ____________________________.

A

Fasciculations (muscle twitches that are visible)

Fibrillations (individual muscle fiber contractions, detected by electromyography)

123
Q

In upper motor neuron lesions is there atrophy?

A

No (if so, it is from disuse)

124
Q

The blood supply to the primary motor and somatosensory cortex comes from the ____________ and _____________ arteries

A

Middle and anterior cerebral arteries

125
Q

Most of the primary motor and somatosensory area is supplied by the ________________ artery.

A

middle cerebral artery

126
Q

The region of the primary motor and somatosensory area related to the lower limb is supplied by the _______________________.

A

Anterior cerebral artery

127
Q

The middle cerebral artery is more or less contiguous with the _______________.

A

internal carotid

128
Q

An embolus that travels through the carotid system is likely to pass into the _________________ artery.

A

Middle cerebral artery

129
Q

About two-thirds of all ischemic stroke occurs in the ______________________ artery.

A

Middle cerebral artery

130
Q

A ischemic stroke affecting even a small region of the internal capsule can produce significant loss of motor and sensory function, why?

A

The blood supply to the internal capsule is by the lenticulostriate branches of the middle cerebral artery, an ischemic stroke in this region (even if small region affected) can produce significant loss of function through damaging many of the crucial axons that pass through the internal capsule (contains both descending upper motor neuron fibers and ascending somatosensory fibers)

131
Q

Why is the internal capsule considered a ‘vulnerable region’?

A

It contains both descending upper motor neuron fibers and ascending somatosensory fibers

132
Q

A transverse cord lesion at a single level of spinal cord results in what loss in function and which structure(s) are affected?

A

Bilateral loss of motor function, upper motor neuron lesion signs

Bilateral loss of somato-sensation

Lateral corticospinal tracts, posterior columns, spinothalamic tracts

133
Q

A hemi-cord (Brown-Sequard Syndrome) lesion at a single level of spinal cord results in what loss in function and which structure(s) are affected?

A

Ipsilateral (same side) loss of motor function (limbs), upper motor neuron lesion signs

Ipsilateral (same side) loss of touch and proprioception

Contralateral (opposite side) loss of pain and temperature

Lateral corticospinal tract, posterior column, spinothalamic tract (sensory information from the other side crosses at the anterior white commissure)

134
Q

Posterior cord syndrome at a single level of spinal cord results in what loss in function and which structure(s) are affected?

A

Bilateral loss of touch and position sense below the level of the lesion

Posterior columns

Could be due to loss of posterior spinal artery supply

135
Q

Anterior cord syndrome at a single level of spinal cord results in what loss in function and which structure(s) are affected?

A

Bilateral loss of motor function

Bilateral loss of pain/temperature sensation below the level of the lesion

Lateral corticospinal tracts and posterior columns

Could be due to loss of anterior spinal artery supply

136
Q

The sympathetic nervous system arises from ____________________ neurons in the _______________horn of spinal levels ____________________.

A

Pre-ganglionic neurons
Lateral horn
T1-L2/L3

137
Q

Pre-ganglionic sympathetic neurons are influenced by descending projections from the ______________________tract located in the __________________________.

A

Hypothalamus (hypo-thalamo-spinal tract)

Located in the lateral funiculus

138
Q

Lesions of the lateral funiculus at T1/T2 and above will damage the ____________________ tract, resulting in loss of sympathetic innervation of the head, this can lead to a condition called Horner’s syndrome.

A

Hypo-thalamo-spinal tract

139
Q

What are the symptoms of Horner’s syndrome?

A

Anhydrosis = decreased sweating; due to loss of innervation of sweat glands in skin (head and body)

Miosis = constricted pupil; due to loss of innervation of pupil dilator muscle

Partial ptosis = a weak, droopy eyelid, due to loss of innervation of the superior tarsal muscle ( a smooth muscle that helps to raise the upper eyelid)

140
Q

Horner’s syndrome is caused by a lesion where?

A

Horner’s syndrome is caused by a lesion in the lateral funiculus at T1/T2 and above damaging the hypo-thalamo-spinal tract.

141
Q

In Horner’s syndrome unilateral lesions produce ______________ loss of function.

A

Ipsilateral

142
Q

Damage to a lateral funiculus above S2-S4 will lead to…

A

Loss of sacral parasympathetic outflow that drive sacral parasympathetics

This can lead to urinary incontinence, bowel incontinence, constipation, and/or loss of sexual function

143
Q

Urinary incontinence, bowel incontinence, constipation, and/or loss of sexual function are often caused by damage to…

A

The lateral funiculus above S2-S4 (loss of sacral parasympathetic outflow that drives pelvic parasympathetics)

144
Q

Fibers from upper motor neurons in the primary motor cortex (frontal lobe, precentral gyrus) travel to the brainstem (via the ______________ and ______________) to form __________________________ fibers to innervate lower motor neurons in cranial nerve nuclei in the brainstem and upper cervical spinal cord.

A

genu of the internal capsule and the crus cerebri

corticobulbar fibers

145
Q

Corticobulbar fibers project mostly ___________ (they are both crossed and uncrossed).

A

Bilaterally

146
Q

Unilateral lesions of upper motor neurons affecting brainstem nuclei, or their corticobulbar fibers, generally do not lead to major loss of function, why? What is the exception?

A

Because corticobulbar fibers project mostly bilaterally (they are both crossed and uncrossed), so crossed projections remain.

The exception is a portion of the facial motor nucleus, which receives only crossed input from upper motor neurons.

147
Q

Match the following:

Upper motor neuron lesion

Lower motor lesion

Weakness/paralysis in lower and upper facial muscles on the same side of the face

Weakness/paralysis in lower facial muscles ONLY

A

Upper motor neuron lesion = weakness in lower facial muscles ONLY

Lower motor neuron lesion = weakness in lower and upper facial muscles on the same side of the face

148
Q

Is paralysis of both upper and lower facial muscles on the side of the lesion, a conditon known as Bell’s palsy associated with UMN lesion or LMN lesion?

A

LMN lesion

149
Q

________________ lesion results in weakness of lower facial muscles only, as _____________ innervating the upper facial muscles receive bilateral input from motor cortex.

A

UMN lesion
LMNs

150
Q

The blood supply to the brainstem gives rise to vascular territories that are typically __________ or ____________ territories. Loss of blood supply to a territory can lead to characteristic _________ or ____________ syndromes.

A

Medial or lateral

151
Q

The medial lemniscus and corticospinal/nuclear tracts are within which vascular territory?

A

Medial

152
Q

The spinothalamic tract is within which vascular territory?

A

Lateral

153
Q

There is a systematic positioning of cranial nerve nuclei by type:

Motor nuclei =
Sensory nuclei =

A

Motor nuclei = medial/anterior
Sensory nuclei = lateral/posterior

154
Q

Which cranial nerve nuclei are affected by a lesion depends on…

A

The level of the brainstem

155
Q

There is a systematic positioning of cranial nerve nuclei by type:

Medial lesions mostly affect ______________ nuclei and fibers

Lateral lesions mostly affect _________________ nuclei and fibers

A

Medial lesions mostly affect somatic motor nuclei and fibers (anterior)

Lateral lesions mostly affect sensory nuclei and fibers (posterior)

156
Q

Deviation of the tongue to the side of lesion, contralateral loss of discriminative touch and conscious proprioception, and/or contralateral spastic hemiparesis are symptoms of what syndrome?

A

Medial medullary

157
Q

Contralateral loss of pain and temperature sensation on the body, ipsilateral loss of pain and temperature sensation on the face, dizziness, vertigo, loss of balance, dysphagia, and/or ipsilateral Horner’s syndrome are signs and symptoms of what type of syndrome?

A

Lateral medullary syndrome

Neuroanatomy (OCCU 6140) (20 decks)

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