Upper Extremity Neuropathies

Question 1

What is the Ape hand deformity?

Answer 1

Compression of median nerve leading to thumb and thenar atrophy

Question 2

What is the sensory distribution of the median nerve?

Answer 2

Pollex, 2nd, 3rd, and half of 4th digit

Question 3

The median nerve supplies all forearm flexors except __________ and the _______ part of __________

Answer 3

Flexor carpi ulnaris
Ulnar part of flexor digitorum profundus

(Supplied by ulnar nerve)

Question 4

What are the autonomous zones of the median nerve?

Answer 4

Area supplied only by the median nerve: Tips of the 2nd and 3rd digit

Question 5

The median nerve supplies all thenar muscles except ______________ and the __________ head of ____________

Answer 5

Adductor pollicis
Flexor pollicis brevis

Both supplied by ulnar nerve

Question 6

Which muscle is used in EMG testing for the median nerve?

Answer 6

Abductor pollicis brevis

Question 7

Name 6 causes of median nerve compression in the axilla

Answer 7

1. Improper use of crutches
2. Missile injuries/stab wounds
3. Improper venipuncture
4. Sleep palsies
5. Humeral head fracture
6. Shoulder dislocation

Question 8

Name the 7 points of entrapment of the median nerve

Answer 8

1. Axilla
2. Next to humerus
3. Elbow
4. Bicipital aponeurosis
5. Pronator teres
6. Sublimis bridge
7. Carpal tunnel

Question 9

What 3 structures in the elbow can cause median nerve entrapment?

Answer 9

1. Struther’s ligament (off medial epicondyle into brachial fascia)
2. Brachialis muscle (MC post-operative)
3. Bicipital aponeurosis

Question 10

What is another name for entrapment of the median nerve in the bicipital aponeurosis?

Answer 10

Lacertus fibrosis

Question 11

What is the sublimis bridge?

Answer 11

Fibrotendinous arcade from origin of FDS muscle

Question 12

What functional test should be done to check for median nerve compression at the elbow?

Answer 12

Pincer grip (lost with. Median nerve compression)

Question 13

The median nerve travels through the carpal tunnel with (#) flexor tendons

Answer 13

9:
FDP (4)
FDS (4)
FPL (1)

Question 14

The median nerve divides into motor and sensory branches (before/after) the carpal tunner

Answer 14

After (except palmar cutaneous sensory branch)

Question 15

What is the MC median nerve compression site?

Answer 15

Carpal tunnel

Question 16

What 6 conditions can cause reduced size of the carpal tunnel, increasing the risk for CTS?

Answer 16

RA
Exostosis/osteophytes
Ganglia
Lipomas/hemangiomas
Gouty tophi
Abnormal muscles and tendons (palmaris longus, lumbricals)

Question 17

Which 3 conditions increase susceptibility to nerve compression?

Answer 17

Polyneuropathy (presdisposes to demyelination)
Diabetic neuropathy
Long term renal dialysis

Question 18

What 4 endocrine/hematological conditions can predispose individuals to CTS?

Answer 18

Polyneuropathy
Multiple myeloma/amyloidosis
Pregnancy
Hypothyroidism

Question 19

____% of pregnant women develop CTS in the 3rd trimester

Answer 19

18-37

Question 20

S&S of carpal tunnel syndrome

Answer 20

Paresthesia and pain
Pain often during sleep
Relief with shaking the hands
Swollen feeling in hands
Pain pattern is sporadic and then continuous
Only one digit may be affected, MC dominant side
Pain referral to arm, shoulder and scapular area (more long-term;
antidromic conduction)
Stiffness when flexing the fingers.

Question 21

Population MC affected by CTS

Answer 21

40-60yo F (3:1)

Question 22

Name 3 orthopedic tests which can be used to test for carpal tunnel syndrome

Answer 22

1. Tinels: tap median nerve at carpal tunnel with reflex hammer, looking for reproduction of symptoms
2. Phalen’s: wrist in flexed posture
3. Reverse phalens: wrist in extended posture

Question 23

How is CTS typically managed?

Answer 23

Conservative for 1 month:

• NSAIDs
• Vitamin B6 100mg daily
• Modify ADLs
• Nighttime wrist splinting
• Carpal tunnel mobilization/manipulation (prevent nerve ischemia)
• Carpal traction (40-60 PSI for 5mins - 5s on, 5s off)

If conservative care fails, surgeryq

Question 24

Which 8 muscles are supplied by the ulnar nerve?

Answer 24

• Flexor carpi ulnaris
• Medial flexor digitorum profundus
• Medial lumbricals
• Abductor digiti minimi
• Flexor digiti minimi
• Opponens digiti minimi
• Palmar interrosei
• Dorsal interossei

Question 25

Which structure marks the point where the ulnar nerve divides into the deep and superficial branches?

Answer 25

Guyon's canal (between hook of hamate and pisiform)

Question 26

MC site of ulnar nerve compression

Answer 26

Cubital tunnel

Question 27

What is the claw deformity?

Answer 27

Chronic atrophy of FPB, AdP, and lumbricals due to ulnar nerve compression

Question 28

Which orthopedic tests can be done to assess for ulnar nerve compression at the elbow?

Answer 28

Tinel's of the ulnar nerve at the cubital tunnel | Elbow flexion test

Question 29

What is Wartenberg's sign?

Answer 29

Slightly greater abduction of the 5th digit due to weakness of paralysis of the adducting palmar interosseous muscle and unopposed action fht eradial innervated extensor muscles

Question 30

How can you tell the difference between ulnar nerve compression at the elbow vs the wrist?

Answer 30

If at wrist, will still have sensation over dorsum of hand, but loss of sensation to palmar side of 4th and 5th digits

Question 31

How is Guyon's canal syndrome (compression of ulnar n) treated?

Answer 31

Wrist splint Protection (avoid further pressure/trauma to pisiform Modalities (EMS< IFC) Surgical decompression

Question 32

The radial nerve innervates which 2 muscles in the upper arm?

Answer 32

Triceps | Brachioradialis

Question 33

The radial nerve innervates which 4 muscles before it crosses the elbow joint?

Answer 33

1. Triceps 2. Brachioradialis 3. ECRL 4. ECRB

Question 34

Below the elbow, the radial nerve splits into which 2 branches?

Answer 34

1. Posterior interosseous nerve | 2. Superficial radial nerve

Question 35

Which 7 muscles are innervated by the posterior interosseous nerve?

Answer 35

extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis

Question 36

What are the 4 compression sites of the radial nerve?

Answer 36

. Axilla 2. Spiral groove 3. Radial tunnel 4. Wrist

Question 37

True or false: one of the key symptoms of radial tunnel syndrome is forearm pain without muscular weakness

Answer 37

True - caused by compression of superficial radial nerve/dorsal antebrachial cutaneous nerve

Question 38

How can you tell the difference between tennis elbow and radial tunnel syndrome?

Answer 38

Location: Tennis elbow: pain at lateral epicondyle Radial tunnel syndrome: pain about 2 inches distal to epicondyle

Question 39

The posterior interosseous nerve can become impinged by the Arcade of ___________ as it travels under the ____________ muscle

Answer 39

Frohse; supinator

Question 40

S&S of posterior interosseous neuropathy

Answer 40

Dull arm pain on anterolateral forearm 2 inches inferior to lateral epicondyle Weak supination and finger extension Tender lateral epicondyle (often misdiagnosed as tennis elbow)

Question 41

One of the key findings to confirm posterior interosseous neuropathy is pain with resisted _______________ of the forearm

Answer 41

Supination

Question 42

DDX for posterior interosseous nerve impingement

Answer 42

``` C7 radiculopathy (will have weakness of triceps and wrist flexors) Lateral epicondylitis Trigger finger (no passive movement possible) Extensor tendon tear ```

Question 43

True or false: posterior interosseous nerve impingement is associated with both motor and sensory deficits

Answer 43

False - no sensory deficits, purely motor