Upper Extremity Neuropathies Flashcards
What is the Ape hand deformity?
Compression of median nerve leading to thumb and thenar atrophy
What is the sensory distribution of the median nerve?
Pollex, 2nd, 3rd, and half of 4th digit
The median nerve supplies all forearm flexors except __________ and the _______ part of __________
Flexor carpi ulnaris
Ulnar part of flexor digitorum profundus
(Supplied by ulnar nerve)
What are the autonomous zones of the median nerve?
Area supplied only by the median nerve: Tips of the 2nd and 3rd digit
The median nerve supplies all thenar muscles except ______________ and the __________ head of ____________
Adductor pollicis
Flexor pollicis brevis
Both supplied by ulnar nerve
Which muscle is used in EMG testing for the median nerve?
Abductor pollicis brevis
Name 6 causes of median nerve compression in the axilla
- Improper use of crutches
- Missile injuries/stab wounds
- Improper venipuncture
- Sleep palsies
- Humeral head fracture
- Shoulder dislocation
Name the 7 points of entrapment of the median nerve
- Axilla
- Next to humerus
- Elbow
- Bicipital aponeurosis
- Pronator teres
- Sublimis bridge
- Carpal tunnel
What 3 structures in the elbow can cause median nerve entrapment?
- Struther’s ligament (off medial epicondyle into brachial fascia)
- Brachialis muscle (MC post-operative)
- Bicipital aponeurosis
What is another name for entrapment of the median nerve in the bicipital aponeurosis?
Lacertus fibrosis
What is the sublimis bridge?
Fibrotendinous arcade from origin of FDS muscle
What functional test should be done to check for median nerve compression at the elbow?
Pincer grip (lost with. Median nerve compression)
The median nerve travels through the carpal tunnel with (#) flexor tendons
9:
FDP (4)
FDS (4)
FPL (1)
The median nerve divides into motor and sensory branches (before/after) the carpal tunner
After (except palmar cutaneous sensory branch)
What is the MC median nerve compression site?
Carpal tunnel
What 6 conditions can cause reduced size of the carpal tunnel, increasing the risk for CTS?
RA Exostosis/osteophytes Ganglia Lipomas/hemangiomas Gouty tophi Abnormal muscles and tendons (palmaris longus, lumbricals)
Which 3 conditions increase susceptibility to nerve compression?
Polyneuropathy (presdisposes to demyelination)
Diabetic neuropathy
Long term renal dialysis
What 4 endocrine/hematological conditions can predispose individuals to CTS?
Polyneuropathy
Multiple myeloma/amyloidosis
Pregnancy
Hypothyroidism
____% of pregnant women develop CTS in the 3rd trimester
18-37
S&S of carpal tunnel syndrome
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.
Population MC affected by CTS
40-60yo F (3:1)
Name 3 orthopedic tests which can be used to test for carpal tunnel syndrome
- Tinels: tap median nerve at carpal tunnel with reflex hammer, looking for reproduction of symptoms
- Phalen’s: wrist in flexed posture
- Reverse phalens: wrist in extended posture
How is CTS typically managed?
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
Which 8 muscles are supplied by the ulnar nerve?
- Flexor carpi ulnaris
- Medial flexor digitorum profundus
- Medial lumbricals
- Abductor digiti minimi
- Flexor digiti minimi
- Opponens digiti minimi
- Palmar interrosei
- Dorsal interossei
Which structure marks the point where the ulnar nerve divides into the deep and superficial branches?
Guyon’s canal (between hook of hamate and pisiform)
MC site of ulnar nerve compression
Cubital tunnel
What is the claw deformity?
Chronic atrophy of FPB, AdP, and lumbricals due to ulnar nerve compression
Which orthopedic tests can be done to assess for ulnar nerve compression at the elbow?
Tinel’s of the ulnar nerve at the cubital tunnel
Elbow flexion test
What is Wartenberg’s sign?
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
How can you tell the difference between ulnar nerve compression at the elbow vs the wrist?
If at wrist, will still have sensation over dorsum of hand, but loss of sensation to palmar side of 4th and 5th digits
How is Guyon’s canal syndrome (compression of ulnar n) treated?
Wrist splint
Protection (avoid further pressure/trauma to pisiform
Modalities (EMS< IFC)
Surgical decompression
The radial nerve innervates which 2 muscles in the upper arm?
Triceps
Brachioradialis
The radial nerve innervates which 4 muscles before it crosses the elbow joint?
- Triceps
- Brachioradialis
- ECRL
- ECRB
Below the elbow, the radial nerve splits into which 2 branches?
- Posterior interosseous nerve
2. Superficial radial nerve
Which 7 muscles are innervated by the posterior interosseous nerve?
extensor digitorum, extensor digiti minimi, extensor carpi ulnaris, abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus, extensor indicis
What are the 4 compression sites of the radial nerve?
. Axilla
- Spiral groove
- Radial tunnel
- Wrist
True or false: one of the key symptoms of radial tunnel syndrome is forearm pain without muscular weakness
True - caused by compression of superficial radial nerve/dorsal antebrachial cutaneous nerve
How can you tell the difference between tennis elbow and radial tunnel syndrome?
Location:
Tennis elbow: pain at lateral epicondyle
Radial tunnel syndrome: pain about 2 inches distal to epicondyle
The posterior interosseous nerve can become impinged by the Arcade of ___________ as it travels under the ____________ muscle
Frohse; supinator
S&S of posterior interosseous neuropathy
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)
One of the key findings to confirm posterior interosseous neuropathy is pain with resisted _______________ of the forearm
Supination
DDX for posterior interosseous nerve impingement
C7 radiculopathy (will have weakness of triceps and wrist flexors) Lateral epicondylitis Trigger finger (no passive movement possible) Extensor tendon tear
True or false: posterior interosseous nerve impingement is associated with both motor and sensory deficits
False - no sensory deficits, purely motor
