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Flashcards in Motor pathways Deck (47)
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1
Q

What do motor nerves do?

A

Voluntary control of movement via skeletal muscle - efferent

2
Q

What does the motor pathway do?

A
  • Synapses with LMN to take signal from spinal cord to muscle
  • UMN is from motor cortex to spinal cord
3
Q

Motor cortex blood supply

A

Anterior/medial posterior cerebral arteries

4
Q

What is the motor cortex formed from?

A

Grey matter

5
Q

Where does the motor neuron cross to the contralateral side?

A

Medulla pyramids

6
Q

When are mixed nerved formed?

A

From the horizontal articular surface, where afferent nerves from the dorsal horn and efferent nerves from the ventral horn combine

7
Q

Where does the right corticospinal tract decussate?

A

Anterior corticospinal tract

8
Q

Which side of the body does the right motor cortex innervate?

A

LHS

9
Q

Where does the anterior corticospinal tract decussate?

A

At exit level in spinal cord

10
Q

Where does the lateral corticospinal tract decussate?

A

Pyramids

11
Q

What does the anterior CST supply?

A

Neck and upper limbs

Fine movements

12
Q

What is a motor unit?

A

A motor neuron and all the muscle fibres it innervates

13
Q

Myotome for shoulder abduction

A

C5

14
Q

Myotome for elbow flexion

A

C5-C6

15
Q

Myotome for wrist extension

A

C6-C7

16
Q

Myotome for finger flexion/extension

A

C7, C8

17
Q

Myotome for finger abduction/adduction

A

T1

18
Q

Myotome for hip flexion

A

L2-L3

19
Q

Myotome for hip extension

A

L4-L5

20
Q

Myotome for knee flexion

A

L2-L3

21
Q

Myotome for knee extension

A

L3-L4

22
Q

Myotome for ankle dorsiflexion

A

L4-L5

23
Q

Myotome for ankle plantar flexion

A

S1-S2

24
Q

How does the stretch reflex work?

A
  • Muscle groups generally work in pairs - flexors/extensors, abductors/adductors etc
  • Contraction of one stretches the other passively - a reflex arc that tenses the stretched muscle
  • Provides muscle tone and stability
  • 2 nerves and 1 synapse - very fast (monosynaptic stretch reflex)
25
Q

What are muscle spindles?

A

Sensory organs in muscles that respond to stretch and position of muscle

26
Q

How is the sensitivity of a muscle spindle controlled?

A

Intrafusal muscle fibres innervated by A-gamma efferents

27
Q

What is the Jendrassik manoeuvre?

A

Clench teeth and fingers and interlock hands
Test knee jerk reflex
Distraction for patient to test reflexes

28
Q

How do you examine tone?

A

Take the weight of a limb and move it around

29
Q

Are fasciculations found in LMN or UMN?

A

LMN

30
Q

Symptoms of neuron damage

A

Weakness, sensory loss, loss of reflexes, respiratory failure

31
Q

Causes of neuron damage

A

MS

Guillon-Barre

32
Q

How do you diagnose Guillou-Barre?

A

Lumbar puncture

33
Q

Characteristic symptom of myasthenia gravis

A

Drooping eyelids

34
Q

What is diplopia?

A

Double vision

35
Q

Examples of UMN injuries

A

Stroke, MS, brain injury, cerebral palsy

36
Q

Examples of LMN injuries

A

Guillon-Barre, trauma, viruses, polio

37
Q

What happens if you have a C4 injury?

A

Quadriplegia / tetraplegia, complete paralysis below neck

38
Q

What happens id you have a C6 injury?

A

Partial paralysis of hands and arms as well as lower body

39
Q

What happens if you have a T6 injury?

A

Paraplegia, paralysis below chest

40
Q

What happens if you have an L1 injury?

A

Paraplegia, paralysis below waist

41
Q

What type of lesion is a brachial plexus injury from a stab wound?

A

Lower

42
Q

What kind of lesion is a stroke from middle cerebral artery thrombosis?

A

Upper

Affects opposite side of body

43
Q

What kind of lesion results from compression of median nerve in the right wrist?

A

Lower

Affects right hand

44
Q

What kind of lesion results from C5 root irritation from spondylosis of cervical spine?

A

Lower

45
Q

What kind of lesion results from transection of spinal cord at C6 after cycle accident?

A

Upper

Affects both sides of body

46
Q

Characteristics of UMN injury

A

Increased tone
Increased reflexes
Upgoing Babinski reflex
No fasciculations

47
Q

Characteristics of LMN injury

A
Decreased muscle tone
Reduced muscle bulk
Decreased reflexes
Downgoing (normal) babinski 
Fasciculations present