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Flashcards in Upper limb nerve injuries Deck (71):
1

Where does the lower motor neuron arise?

Anterior horn

2

Describe the characteristics of an upper motor neuron pathology

Held in flexed posture if chronic.
Increased tone
Pyramidal weakness (Flexor muscles stronger than extensors)
Brisk reflexes.
Sensory level

3

Describe the characteristics of a lower motor neuron pathology

Wasting/Fasciculations
Flaccid tone
Weakness in either a myotomal distribution or a peripheral nerve distribution
Reduced reflexes.
Dermatomal or peripheral nerve distribution of sensory loss.

4

Name the 3 anatomical regions for localizing a lesion

Roots
Brachial plexus
Peripheral nerves

5

What are myotomes

Relationship between spinal nerve and muscle

6

What are dermatomes?

Relationship between spinal nerve and skin

area of the skin supplied by nerve fibres originating from a single dorsal nerve root. 

7

Where is there a lot of anatomical variation?

In dermatomes

8

What is the myotome of C5?

Deltoid

9

What is the myotome of C6?

Biceps
Brachialis
Brachioradialis

10

What is the myotome of C7?

Triceps
Superficial forearm extensors
Superficial forearm flexors

11

What is the myotome of C8?

Forearm extensors
Deep forearm flexors

12

What is the myotome of T1?

Intrinsic hand muscles

13

What muscle action does the C5 myotome perform?

Shoulder abduction

14

What muscle action does the C6 myotome perform?

Elbow flexion

15

What muscle action does the C7 myotome perform?

Elbow extension
Wrist extension
Wrist flexion

16

What muscle action does the C8 myotome form?

Finger extension
Finger flexion

17

What muscle action does T1 myotome form?

Finger abduction

18

What is the name of the C5 reflex?

Biceps reflex

19

Which nerve conveys the biceps reflex?

Musculocutaenous

20

What is the name of the C6 reflex?

Supinator jerk

21

Which nerve conveys the supinator jerk

Radial nerve

22

What is the name of the C7 reflex?

Triceps jerk

23

Which nerve conveys the triceps jerk?

Radial nerve

24

What is the name of the C8 reflex?

Finger jerk

25

Which nerve conveys the finger jerk?

Median and ulna nerve

26

What happens to reflexes in lower motor neuron lesions?

Reflex is depressed

27

What does nerve root impingement cause?

Pain which radiates or is aggravated by neck movement

Sensory loss

Weakness

Reflex loss

28

What causes nerve root impingement?

Hyperflexion and extension

29

What is an avulsion?

Tearing of the nerves from its attachment at the spinal cord.

30

What is a rupture?

Tearing of the nerves but not from its attachment to the spinal cord

31

What is a neuroma?

tumour or growth of the nerve tissue. Can arise from the axon or myeloma

32

What is a neurapraxia?

Axons remain intact, but myelin damage cause an interruption of the impulse down the nerve fibre

33

What is flail arm?

Cervical root avulsion

34

Name some conditions as a result of trauma to the brachial plexus

Erb-Duchenne type paralysis: Avulsion of C5,C6 roots.

Klumpke paralysis: Avulsion of C8, T1 roots.

35

Name a tumour affecting the brachial plexus

Pancoasts tumour - lung cancer

36

Which cancer treatment may cause injury to the brachial plexus?

Radiotherapy

37

Name an inflammatory injury of the brachial plexus

Brachial neuritis

38

Name a structural injury to the brachial plexus

Thoracic outlet syndrome

39

Name the muscles weakened in erbs palsy

Biceps (flexes the arm)
Brachioradialis (flexes the arm in semi-prone position)
Deltoid (abducts the arm)
Supraspinatus (abducts the arm)
Supinator (externally rotates the arm)

40

What is erbs palsy?

- upper plexus palsy
C5/C6 innervated muscles
Superior trunk of brachial plexus

41

What causes erbs palsy?

Infants - birth and getting shoulder stuck
Adults - blow to the shoulder

42

What is another name for erbs palsy lesion?

Waiters tip

43

What actions can and cannot a person with erbs palsy perform?

Elevated
Abducted
External rotated
Flexed at elbow

But fingers unimpaired

44

Describe Klumpke’s Palsy

Clutching for an object when falling from a height.
- Inferior trunk plexus injury involving C8/T1

Involves trunk that supplies median and ulnar nerves

Unable to flex wrist or fingers
Weakness of all small muscles of the hand
Sensory loss hand and inner border of forearm

May lead to a claw hand

Arm works but hand
does not!

45

Describe a pancoast tumour

infiltration of the lower brachial plexus
Pain in shoulder girdle and inner arm.
Ipsilateral horners syndrome

46

Describe radiation induced brachial plexopathy

Mean 6 yrs post radiation
Associated with treatment for breast, lung cancer and lymphoma
Pain is not a consistent feature
Predilection for upper brachial plexus

47

Describe Idiopathic brachial neuritis (Parsonage – Turner Syndrome)

Aetiology not clear, infectious, post-infectious
Severe pain over days; as pain diminishes, it is followed by weakness and wasting (motor>sensory)
Typically monophasic
Rarely bilateral
MRI shows thickening and enhancement.
NCS/EMG is useful for prognostication.

48

Give the treatment of Idiopathic brachial neuritis (Parsonage – Turner Syndrome)

Analgesia, physiotherapy
Limited evidence for the use of steroids

49

Describe thoracic outlet syndrome

Variations in anatomy cause compression sites:
Between anterior and middle scalene muscles
Beneath clavicle in the costoclarvicular space
Beneath tendon of Pectorlis minor

50

List some neurogenic symptoms of thoracic outlet syndrome

Paresthesia, numbness, weakness
Not localised to specific nerve distribution
Reproducibly aggravated by elevation or sustained use of arms or hands.

51

List some vascular symptoms of thoracic outlet syndrome

Forearm fatigue within minutes of use.
Swelling and cynaosis
Collateral venous patterning over the ipsilateral shoulder, chest wall and neck.
Rarely pain, pallor and coldness (arterial involvement).
Lower BP on affected arm, diminished distal pulses.

52

When may the long thoracic nerve be injured?

Long thoracic nerve
may be injured by blows or pressure
in the posterior triangle of the neck

or during a radical mastectomy.

53

What can injury of the long thoracic nerve lead to?

‘winged scapula’

54

Describe how injury to the long thoracic nerve results in winged scapula

Long thoracic nerve supplies the serratus anterior muscle.
The serratus anterior muscle pulls the medial border of the scapula
to the posterior thoracic wall and stabilises it there
Impairment of the long thoracic nerve leads to “winging” of the scapula

55

List 2 common sites of nerve compression

Wrist (Carpel tunnel syndrome)
Elbow

56

Which hand muscles does the median nerve innervate?

L ateral 2 lumbricals
O pponens pollicis
A bductor pollicis brevis
F lexor pollicis brevis

57

List some causes of carpal tunnel syndrome

Diabetes
Pregnancy
Hypothyroidism
Rheumatoid arthritis
Repetitive strain

58

Where does the Anterior interosseous nerve arise?

from median nerve just above elbow.

59

Describe how damage to the anterior interosseous nerve may occur

Prone to compression between 2 heads of
pronator teres muscle

Gripping tightly with forced pronation

Prolonged use of a screwdriver!


May also be damaged in careless blood taking

60

Describe anterior interosseous nerve syndrome

Pure motor branch of the median nerve
weakness in flexors of ip joint of thumb (flexor policis longus)
& dip joints of index and middle fingers – (flexor digitorum profundus)
weakness of pronation

61

Describe the ulnar claw of a higher lesion in the upper limb

Paralysis of the ulnar half of the flexor digitorum profundus (FDP), interossei and lumbricals. The ring and little fingers are not flexed and there is no claw.

62

Describe the ulnar claw of a lower lesion in the upper limb

Flexion at the DIP (FDP is intact)
Flexion at the PIP (interossei are paralysed)
hyperextention at the MCP (lubricals are paralysed).

63

Where is the deep ulnar nerve?

Guyon’s canal

64

What does the deep ulnar nerve do?

motor only to intrinsic hand muscles

65

How can the deep ulnar nerve be injured?

Occupation, cycling, rheumatoid arthritis

66

What leads to the Froment’s sign?

Weakness of adductor pollicis

67

Describe radial nerve palsy?

Radial nerve damage rarely causes extensive sensory loss
Extensive overlap with median/ulnar excepting anatomical snuff box

68

What are nerve conduction studies useful for?

Useful in determining the amplitude and velocity of a peripheral nerve

69

What does axonal loss lead to?

decrease in amplitude

70

What does demyelinating lead to?

decrease in velocity

71

What does needle EMG measure

electrical activity of the muscle during voluntary contraction. The pattern of the electrical activity can help distinguish a lesion arising from the nerve (neurogenic) vs muscle (myopathic)