Clinical neurophysiology Flashcards

1
Q

What are the different sections of the brachial plexus?

A
  • roots
  • trunks
  • divisions
  • cords
  • nerves (median, ulnar and radial)
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2
Q

What three nerves does the brachial plexus end in?

A
Musculocutaneous 
axillary 
radial 
median 
ulnar
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3
Q

What does the median nerve supply?

A

thumb, index, middle and half ring finger

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4
Q

What does the ulnar nerve supply?

A

pinky and half ring finger

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5
Q

What does the radial nerve supply?

A

dorsal hand

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6
Q

What motor fibres does the median nerve supply?

A

median muscle forearm (proximal and distal) and hand

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7
Q

What nerve root fibres make up the median nerve?

A

C5 + C6 (lateral cord)

C8 + T1 (medial cord)

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8
Q

What is the primary function of the lateral and medial cord of the median nerve?

A

lateral is mainly sensory

medial is mainly motor

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9
Q

What nerve branches of the median nerve at the elbow?

A

anterior interosseous nerve

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10
Q

What is the most common median nerve pathology?

A

Carpal tunnel syndrome (entrapment neuropathy)

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11
Q

Who is entrapment of median nerve most common in?

A

females

45-65 yrs

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12
Q

What would be the main differential diagnosis of carpal tunnel syndrome?

A

Lesion of:

  • C6-7
  • Brachial plexus
  • Proximal median nerve lesion
  • motor neurone disease (shouldnt have sensory disturbance)
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13
Q

What are the symptoms of carpal tunnel syndrome?

A
  • paraesthesia in median distribution (can present as whole hand)
  • worse during sleep/ on wakening
  • loss of dexterity
  • can present in dominant hand first
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14
Q

What are the risk factors for carpal tunnel?

A
  • small carpal tunnel
  • diabetes mellitus
  • inflammatory conditions
  • pregnancy, menopause and obesity
  • hypothyroidism or renal disorder
  • occupational (farmers)
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15
Q

Where will sensation often be spared in carpal tunnel?

A

thenar eminence as supplied by palmar cutaneous sensory branch

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16
Q

What are the tests for the hand?

A

Tinels (hand tapping)

Phalens (pushing dorsal aspect of hands against each other, hold at shoulder level for 60s)

17
Q

What would motor examination of carpal tunnel syndrome show?

A

wasting thenar eminence

weakness thumb abduction and opposition

18
Q

What muscles are supplied by the anterior interosseous nerve?

A

flexor digitorum profundus (flex distal phalanx or index and middle finger)
flexor pollicus longus (flexes distal phalanx thumb)
Pronator quadratus

19
Q

How would weakness of anterior interosseous nerve present?

A
  • weakness of flexor pollicus longus
  • no sensory symptoms
  • normal abductor pollicus brevis
  • can’t work lighter or take photo on camera
20
Q

Where is Ulnar nerve most commonly trapped?

A

elbow

21
Q

Which roots is ulnar nerve derived from?

A

C8-T1

22
Q

What are the branches of the ulnar nerve?

A
  • dorsal cutaneous branch (dorsal part of hand on ulnar border)
  • palmar cutanoues branch (palmar area on ulnar border)
  • superficial terminal branches (pinky and half ring finger)
23
Q

What is the most common ulnar neuropathy?

A

compression
stretch
elbow injury

24
Q

What are the motor symptoms of ulnar neuropathy?

A
  • decreased grip and pinch
  • atrophy of hypothenar eminence and intrinsic hand muscles
  • claw hand
25
Q

If Ulnar damage is at the wrist which branches will be spared?

A
  • dorsal cutaneous and palmar cutaneous

- meaning only sensory disturbance at fingers not at rest of hand

26
Q

What will lesion at medial cord result in?

A

finger, hand and forearm

27
Q

What will ulnar lesion at elbow affect?

A

finger and hand (forearm not affected)

28
Q

What causes wrist drop?

A
CNS lesion 
C7/8 radiculopathy 
brachial plexopathy 
spiral groove 
PIN
29
Q

Why do you get wrist drop?

A

weakness of wrist muscles

30
Q

What does sensory involvement of wrist drop tell us?

A

lesion must be above where posterior interosseous nerve branches off (elbow)

31
Q

If there is no sensory involvement with wrist drop what is the cause?

A

damage to the posterior interosseous nerve

32
Q

What nerve does the posterior interosseous nerve branch from?

A

Radial