Exam #6: Corticomotor Function Flashcards Preview

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Flashcards in Exam #6: Corticomotor Function Deck (27):
1

What is the origin, termination, and function of the corticospinal pathway?

Lateral corticospinal tract
- Origin= motor areas of cerebral cortex
- Termination= lateral neurons in ventral horn
- Function= control of distal/ lateral muscles of the body

Anterior corticospinal tract
- Origin= motor areas of cerebral cortex
- Termination= anterior neurons in ventral horn
- Function= control of proximal muscles of the body

2

What is the origin, termination, and function of the corticonuclear (corticobulbar) pathway?

Origin= motor areas of the cerebral cortex
Termination= muscles of the head & neck
Function= motor output to muscles of the head and neck

3

What is the origin, termination, and function of the rubrospinal pathway?

Origin= red nucleus
Termination= same muscles as upper lateral corticospinal tract
Function= questionable role in arm, hand, and finger movement

4

List the effects of lesions in the corticospinal tract.

1) Weakness
2) Extensor plantar reflex

5

Where is the motor cortex located, and what is its function?

Brodmann 4
- Voluntary movement i.e. implementation of the motor plan

6

Where is the premotor cortex located, and what is its function?

Brodmann 6
- Motor planning and learning activated or guided by external stimuli

*Develops the "motor plan" that is transmitted to the primary motor cortex

7

Where is the supplementary motor area, and what is its function?

This is a subset of nuclei located in Brodmann 6 (premotor cortex)
- Motor planning and preparing for sequential motor acts influenced by internal stimuli
- Coordinates movement between sides of the body
- Anticipatory postural adjustments

*Develops the "motor plan" that is transmitted to the primary motor cortex

8

Where are the frontal eye fields located, and what are their functions?

Brodmann 8
- Influences voluntary and memory guided eye movements

9

Describe the presentation of a lesion to the motor cortex.

A small lesion to the primary motor cortex will produce contralateral weakness without spasticity

10

Describe the presentation of a lesion to the premotor cortex.

Premotor area has a role in visually guided movement e.g. reaching & grasping

11

Describe the presentation of a lesion to the supplementary motor area.

Difficulty initiating or suppressing movement

12

Describe the presentation of a lesion to the frontal eye fields.

- Inability to make saccades not guided by an external target
- Cannot voluntarily direct eyes away from a stimulus

13

What is the difference between an ACA & MCA infarct based on the rough topographical map of the motor cortex?

ACA=
- Leg area of primary motor cortex
- Supplementary motor cortex
- Cingulate gyrus

MCA=
- Trunk, hand, and face area of primary motor cortex
- Premotor area

14

What is quadriplegia? What is tetraplegia?

These are two different terms for the same thing: paralysis of four limbs
- Caused by cervical transection

15

What is paraplegia?

Paralysis of lower two limbs
- Caused by transection below the cervical spine

16

What is paresis?

Weakness to voluntary muscle

17

What is quadriparesis?

Weakness in all four limbs

18

What is hemiparesis?

Weakness in one half of the body (2x limbs)

19

What is monoplegia?

Weakness to one limb

20

Explain the crossed paralysis found with some brain stem lesions.

Crossed paralysis is found in brainstem lesions & produces an "alternating hemiplegia"

21

List the symptoms and signs associated with an upper motor lesion.

Hyperreflexia
Hypertonia
Primitive reflexes

22

List the symptoms and signs associated with a lower motor lesion.

Weakness
Hypotonia
Hyporeflexia

23

Explain the pathophysiology of Brown-Sequard Syndrome.

This is a hemisection of the spinal cord that causes motor and sensory deficit
- No feeling at the level, ipsilateral to the lesion
- DC/ML lost on ipsilateral side
- Pain & temperature lost contralateral

- Monoplegia ipsilateral to the lesion
- Ipsilateral Babinski

24

What are the effects of lesions in the internal capsule (general motor and sensory deficits)?

Loss of motor and sensory contralateral to the side of the lesion

25

What is the effect of lesions of the upper motor neurons in the motor cortices on the control of the upper and lower facial muscles?

UMN lesions result in weakness of the contralateral inferior facial muscles

26

What is the effect of lesions damaging the facial nucleus or the facial nerve?

LMN lesions result in weakness of the contralateral facial muscles

27

What is the difference between superior, middle, and inferior alternating hemiplegia?

Primarily, location of the brainstem lesion
- Superior= midbrain
- Middle= pons
- Inferior= medulla

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