Upper extremity

Question 1

Median nerve

Answer 1

Differentiate from

1. ) C6/C7 root lesion
2. ) Proximal median neuropathy
3. ) brachial plexopathy

Question 2

Median nerve: course

Answer 2

1.) adjacent to brachial artery in antecubital fossa

2. ) passes through Pronator Teres, supplies:
   - Pronator teres
   - flexor carpi radialias
   - palmaris longus
   - flexor digitorum sublimis
3. ) Next, AIN
   - Flexor digitorum profundus (FDP 2,3)
   - Flexor Pollicus Longus (FPL)
   - Pronator Quadratus (PQ)

4.) proximal to wrist: palmar cutaneous sensory nerve (thenar eminence)

5. ) carpal tunnel: sensory and motor branches
   - Motor: L(1,2)OAF

Question 3

Causes Carpal Tunnel

Answer 3

• hypothyroidism
• pregnancy
• diabetes
• rhematoid arthitis
• amyloidosis
• Sarcoid
• Lyme
• TB
• Trauma

Question 4

Clues to C6/C7 radiculopathy

Answer 4

• Neck pain
• Weakness: pronation, elbow flexion/extension
• Sensory abnormalities in palm/forearm
• decreased reflexes

Question 5

Clues to proximal median neuropathy

Answer 5

• sensory abnormalities over thenar eminence

- weakness of proximal muscles: thumb flexion (Flexor pollicis longus), pronation (PT/PQ), wrist flexion (FCR)

Question 6

Proximal Median Neuropathy

Answer 6

Entrapment syndromes:

1. ) ligament of struthers entrapment
   - weakness of PT and all median innervated nerves
   - -> bony spur may be palpable
2. ) Pronator syndrome
   - pain in forearm; exacerbated by repeated pronation/supination
   - median pattern paresthsias (including thenar)
   - Pronator Teres is SPARED
   - weakness/wasting rare
3. ) AIN
   - unable to flex thumb at IP
   - unable to flex index/middle at DIP
   - weakness of pronation
   - cant demonstrate “OK” sign–> patients instead clamp the sheet of paper with extended thumb and index finger

Question 7

Ulnar nerve: course

Answer 7

Descends medial side

1. ) Goes through Arcade of Struthers
2. ) enters ulnar groove at elbow
3. ) proximal forearm, goes under cubital tunnel
   - flexor carpi ulnaris
   - flexor digittorum profundus (4,5)
4. ) proximal at wrist:
   - dorsal ulnar cutaneous branch
   - palmar ulnar cutaneous branch
5. ) entering Guyon’s canal
   - sensation to volar 5th and medial 4th digit
   - Motor:
   a. ) FDI
   b. ) abductor digiti minimi
   c. ) flexor digiti minimi
   d. ) opponens digiti minimi
   e. ) palmar interossei
   f. ) Lumbricals (4,5)
   g. ) adductor pollicus
   h. ) flexor pollicus brevis

Question 8

Ulnar Neuropathy Elbow

Answer 8

• All innervated muscles
• Sensory loss
• *involvement of dorsal ulnar territory excludes ulnar neuropathy at wrist (bc dorsal ulnar cutaneous sensory nerve is proximal to wrist)

**involvement of medial forearm implies lesion of plexus or roots
Medial antebrachial cutaneous sensory nerve arises directly from medial cord

Question 9

UNE-hand postures

Answer 9

1. ) Benediction posture
   - clawed posture of 4th and 5th digits, slight abduction of fingers and thumb (lumbrical weakness, palmar interossei weakness, adductor pollicus weakness
2. ) Wartenburg’s sign
   - abducted pinky (3rd palmar interossei weakness)
3. ) Froment’s sign
   - abnormal pinch (look up)
4. ) ulnar grip
   - incomplete flexion of 4th and 5th digits
   - FDP 4/5 weakness

Question 10

UNW

Answer 10

Subtypes of UNW

1. ) Distal deep palmar motor lesion
   - all muscles supplied except hypothenar
2. ) proximal deep palmar lesion
   - all muscles except palmaris brevis
3. ) proximal canal lesion
   - all branches of ulnar nerve past wrist
4. ) superficial palmar lesion
   - all sensation (medial 4th and 5th digit)

Same hand postures as UNE

Causes: occupational (tool use, bikers), ganglion cyst, trauma, wrist fracture

Question 11

Radial Nerve

Answer 11

1. ) gives off sensory branches: posterior cutaneous nerve of arm and forearm
2. ) then branch to 2 musclesl: triceps, anconeus
3. ) wraps around posterior humerus (via spiral groove)
4. ) IN elbow: brachioradialis, extensor carpi radialis longus
5. ) distal to the lateral epicondyle: superficial radial sensory nerve (lateral dorsal hand sensation), deep radial motor branch (extensor carpi radialis brevis, supinator)–> enters Arcade of Frohse (via supinator), becomes PIN
6. ) PIN
   - Extensor carpi ulnaris
   - Extensor digitorum communis
   - Extensor digiti minimi
   - Abductor pollicus longus
   - Extensor pollicus longus
   - Extensor pollicus brevis
   - Extensor indicies proprius (EIP)

**etiology of PIN: reptitive supination/pronation, tumor proximal forearm

Question 12

Radial Neuropathy-Spiral Groove

Answer 12

• most common entrapment site
• MOTOR: wrist drop, mild weakness of supination and elbow flexion

-SENSATION: lateral dorsum of hand, thumb, dorsal proximal fingers 2-4 (4th only lateral side)

Question 13

Radial Neuropathy-Axilla

Answer 13

Motor: weakness of triceps + spiral groove neuropathy

Sensory: loss in posterior forearm/arm

Etiology: crutches

Question 14

Superficial Radial Sensory neuropathy

Answer 14

“Cheirlagia Paresthetica”

• compression of superficial radial sensory nerve in distal forearm
• no weakness

Etiology: compression tight wrist bands, watches, bracelets, etc.

Question 15

Axillary Neuropathy

Answer 15

• partial weakness shoulder abduction and external rotation
• -lateral shoulder girdle atrophy and sensory loss

Etiology: shoulder dislocation/humerous fracture, sports, etc

Question 16

Musculocutaneous Neuropathy

Answer 16

• weakness of elbow flexion
• absent biceps DTR
• sensory loss over lateral forearm (lateral cutaneous nerve of forearm)

Question 17

Etiology Ulnar Neuropathy at Wrist

Answer 17

Ganglion cyst within Guyon canal
Ulnar artery aneurysm
Lipomas
Bikers (repetitive movements)