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Year 2 - T3 Theme 2 > L11 - Upper limb nerve injuries > Flashcards

L11 - Upper limb nerve injuries Flashcards

1
Q

UMN presentation in the upper limb

A
  • Held in flexed posture if chronic
  • Increased tone
  • Pyramidal weakness (flexor muscles stronger than extensors)
  • Brisk reflexes
  • Sensory level
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2
Q

LMN presentation in the upper limb

A
  • 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
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3
Q

Anatomical localisation of lesion

A

3 anatomical regions for localising the lesion:

Roots
Brachial plexus
Peripheral nerve

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4
Q

Myotomes

A
  • Relationship between the spinal nerve and muscle
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5
Q

Dermatomes

A
  • Relationship between the spinal nerve and skin
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6
Q

Link between sensory findings and dermatomes

A
  • Sensory findings on examination do not always demarcate in line with the dermatomes
  • It may not involve the whole dermatome and maybe absent
  • Two-point discrimination is a very sensitive test
  • Pain can spread to involve other dermatomes
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7
Q

Deltoid - root and action

A
  • C5

- Shoulder abduction

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8
Q

Biceps, brachialis and brachioradialis - root and action

A
  • C6

- Elbow flexion

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9
Q

Triceps, superficial forearm extensors and forearm flexors

A
  • C7

- Elbow extension and wrist extension + flexion

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10
Q

Forearm extensors and deep forearm flexors - root and action

A
  • C8

- Finger extension + flexion

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11
Q

Intrinsic hand muscles - root and action

A
  • T1

- Finger abduction

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12
Q

Biceps reflex

A
  • C5 reflex conveyed through the musculocutaneous nerve
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13
Q

Supinator jerk

A
  • C6 reflex conveyed through the radial nerve
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14
Q

Triceps jerk

A
  • C7 reflex conveyed through the radial nerve
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15
Q

Finger jerk

A
  • C8 reflex conveyed through the median and ulnar nerve
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16
Q

When is a reflex depressed

A
  • Lower motor neuron lesions
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17
Q

Nerve root impingement

A

Causes - pain - radiates/aggravated by neck movement

  • Sensory loss
  • Weakness
  • Reflex loss

Flexibility of cervical spine protects it from fractures or dislocation-but may get injury to neural structures - hyper flexion/extension

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18
Q

Avulsion

A
  • Tearing of the nerves from its attachment at the spinal cord
  • Requires surgical repair
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19
Q

Rupture

A
  • Tearing of the nerves but not from its attachment to the spinal cord
  • Requires surgical repair
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20
Q

Neuroma

A
  • Tumour or growth of the nerve tissue. Can arise from the axon or myeloma
  • Requires surgical repair
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21
Q

Neurapraxia

A
  • Axons remain intact, but myelin damage cause an interruption of the impulse down the nerve fibre - good prognosis
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22
Q

Motor cycle injury - flail arm (cervical root avulsion)

A
  • C5-T1 lesions causing flail arm
  • Left shoulder subluxation
  • Atrophy of the left deltoid, supraspinatus and infraspinatus
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23
Q

Brachial plexus injury - trauma

A
  • Erb-duchenne type paralysis, avulsion of C5,C6 roots

- Klumpke paralysis: Avulsion of C8, T1 roots

24
Q

Brachial plexus injury - cancer

A
  • Lung cancer - pancoasts tumour

- Radiotherapy

25
Q

Brachial plexus injury - inflammation

A
  • Brachial neuritis
26
Q

Brachial plexus injury - structural

A
  • Thoracic outlet syndrome
27
Q

Erbs palsy

A
  • Upper plexus palsy, C5/C6 innervated muscles

- Superior trunk of brachial plexus(adults - blow to shoulder)

28
Q

Affected muscles in erbs palsy

A 
Weak muscles include - 
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)
29
Q

Movements limited by erbs palsy

A

Arms cannot be:

  • Elevated
  • Abducted
  • Externally rotated
  • Flexed at elbow

but fingers unimpaired, hand works but arm does not

30
Q

Klumpke’s palsy

A

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
31
Q

What can klumpke’s palsy lead to

A
  • May lead to a claw hand

- Arm works but hand does not

32
Q

Metastatic brachial plexopathy

A

Pancoast tumour (lung) - infiltration of the lower brachial plexus

  • Pain in shoulder girdle and inner arm
  • Ipsilateral horners syndrome
33
Q

Radiation induced brachial plexopathy

A
  • 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
34
Q

Idiopathic brachial neuritis (parsonage - turner syndrome) - IBN

A
  • 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
35
Q

Treatment for idiopathic brachial neuritis

A
  • Analgesia, physiotherapy

- Limited evidence for the use of steroids

36
Q

Thoracic outlet syndrome

A

Variations in anatomy cause compression sites:

  • Between anterior and middle scalene muscles
  • Beneath clavicle in the costoclavicular space
  • Beneath tendon of pectoralis minor
37
Q

Thoracic outlet syndrome - neurogenic

A
  • Paresthesia, numbness, weakness
    • Not localised to specific nerve distribution
    • Reproducibly aggravated by elevation or sustained use of arms or hands.
38
Q

Thoracic outlet syndrome - vascular

A
  • Forearm fatigue within mins of use
  • Swelling and cyanosis
  • 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
39
Q

When might the long thoracic nerve be damaged

A
  • May be injured by blows or pressure in the posterior triangle of the neck or during a radical mastectomy
  • Leads to a ‘winged scapula’
40
Q

2 common sites for compression of median nerve

A
  • Wrist (carpal tunnel syndrome)

- Elbow

41
Q

Median nerve innervated hand muscles

A

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

42
Q

Causes of carpal tunnel syndrome

A
  • Diabetes
  • Pregnancy
  • Hypothyroidism
  • Rheumatoid arthritis
  • Repetitive strain
43
Q

Where does the anterior interosseous nerve arise from

A
  • Median nerve just above elbow
  • 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
44
Q

Anterior interosseous nerve syndrome

A
  • Pure motor branch of the median nerve
  • Weakness in flexors of ip joint of thumb (flexor pollicis longus) and dip joints of index and middle fingers - (flexor digitorum profundus) weakness of pronation
45
Q

Higher lesion in the upper limb

A
  • 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
46
Q

Lesion at the wrist

A
  • Flexion at the DIP (FDP is intact)
  • Flexion at the PIP (interossei are paralysed)
  • Hyperextension at the MCP(lumbricals are paralysed)
47
Q

Sensory innervation of ulnar nerve lesion localisation

A

check diagrams in notes

48
Q

Ulnar nerve, around medial epicondyle

A
  • Superficial sensory branch comes off in distal forearm above wrist
  • Deep ulnar branch, guyton’s canal motor only to intrinsic hand muscles
  • Occupation, cycling, rheumatoid arthritis
49
Q

Froment’s sign

A
  • Weakness of adductor pollicis leads to froment’s sign

- Sign of ulnar palsy

50
Q

Ulnar vs C8

A

C8

  • All finger extensors (radial nerve)
  • FDP of index/middle (median nerve)
51
Q

‘Saturday night palsy’

A
  • Radial nerve palsy
  • Radial nerve damage rarely causes extensive sensory loss
  • Extensive overlap with median/ulnar excepting anatomical snuff box
52
Q

Usefulness of nerve conduction studies

A
  • Useful in determining the amplitude and velocity of a peripheral nerve
53
Q

Effect of axonal loss on nerve conduction

A
  • Decrease in amplitude
54
Q

Effect of demyelination on nerve conduction

A
  • Decrease in velocity
55
Q

Neurogenic vs myogenic

A

Needle EMG measures 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)

Year 2 - T3 Theme 2 (17 decks)

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