Neuro - Upper limb

Question 1

Describe sensory and motor weakness in median nerve lesion

Answer 1

Sensory loss palmar 1st 3 fingers
Weakness/wasting in APB, FDP (benediction sign)
Muscles: LOAF (lateral 2 lumbricals, OP, APB, FPB)

Question 2

Describe sensory and motor weakness in ulnar nerve lesion

Answer 2

Sensory loss last 2 fingers
Wasting of ADM and 1st dorsal interosseous
Weakness in ADM, 1DI, pinky FDP (in severe)
Deep palmar branch lesion - weakness of index finger Abd

Question 3

Wrist drop - weakness of brachioradialis, wrist extension, finger extension?

Answer 3

Radial nerve lesion in spiral groove (triceps spared)

Question 4

Wrist drop - radial deviation of wrist, weakness of finger extension?

Answer 4

Posterior interosseous branch of radial nerve lesion (ECU weakness)

Question 5

Wrist drop - radial deviation, weakness of finger ext+flex, weakness of triceps, loss of triceps reflex

Answer 5

C8/T1 lesion

Question 6

UMN weakness of abduction, extensors of upper limb

Answer 6

Corticospinal lesion - look for hemiparesis in leg/face

Question 7

Ix for mononeuritis multiplex

Answer 7

NCS
EMG
CSF
Metabolic - glucose, vasculitic screen, anti GM1, anti GQ1b, HIV, hep C/cryoglobulins, ACE

Question 8

Wrist drop causes

Answer 8

1. Weakness of ECRL - C5/6 or radial n

2. Weakness of ECU - C7/8, posterior interosseous branch of radial n

Question 9

Ix for myopathy

Answer 9

EMG
Muscle biopsy
ESR/CRP, CK, AI screen

Question 10

EMG in neuropathy vs myopathy

Answer 10

1. neuropathy - increased insertional activity, fibrillation, spontaneous activity, large MUP (motor unit potentials)
2. myopathy - small MUP, early recruitment, low amplitude

Question 11

NCS in axonopathy vs demyelination

Answer 11

1. axonopathy - fasiculations, low amplitude

2. demyelination - slow conduction, prolonged distal latency, conduction block, prolonged f-wave latency

Question 12

Weakness of deltoid, biceps, brachioradialis?

Answer 12

C5/6 lesion

-deltoid only + shoulder patch sensory loss = axillary n. lesion

Question 13

Weakness of C5/6 (deltoid, biceps, BR)
Loss of biceps and BR reflex
Hyperreflexic triceps

Answer 13

C5/6 cord lesion - ie. C8/T1 triceps is hyperreflexic below that level

Question 14

How to check the level of a C5/6 lesion?

Answer 14

Proximal - all weak
Next - serratus anterior spared (long thoracic n.)
Distal - supra/infraspinatus spared (suprascapular n)

Question 15

LMN arm weakness - proceed

Answer 15

Horners syndrome

C5-T1 sensory level - if dissociated -> syringomyelia

Question 16

UMN arm weakness - proceed

Answer 16

R arm - check aphasia

L arm - check neglect, construction apraxia

Question 17

Proximal arm and leg weakness in a patchy pattern - DDx

Answer 17

Muscular dystrophy *brachioradialis wasting
Spinal muscular atrophy
IBM
MG