MSK 2: Clinical Correlations + Imaging of UE

How to elicit deep tendon reflexes

Tap on end of tendon to elicit reflex to test if nerve intact

-ie. + reflex s/p tapping on biceps tendon → can assume C5 and C6 are still intact/ functional

-ie. + reflex s/p tapping on triceps tendon → can assume C7 and C8 are still intact/ functional

What is Erb-Duchenne Palsy?

Upper Trunk Lesion

Typically C5 and C6 involved

Clinical Presentation:

-affected arm is adducted, medially rotated, forearm is extended

-diminished sensation over lateral arm and forearm

What muscles/ muscle actions are affected with Erb-Duchenne Palsy?

Deltoid and Supraspinatus - arm abduction

Biceps and Brachialis - forearm flexion

Teres Minor and Infraspinatus - arm lateral rotation

What is Klumpke Paralysis?

Lower Trunk Lesion

Clinical Presentation:

-Weakness in hand functions

-Diminished sensation along the ulnar border of the forearm and hand

-Reduced wrist flexion

TOTAL Claw Hand - hyperextension at the MCP joints and flexion at the IP joints

What muscles/ muscle actions are affected with Klumpke Paralysis?

Hypothenar mm. - 5th digit

Interossei - ab/adduction of fingers

Medial 2 lumbricals and lateral 2 lumbricals

Medial 2 FDP mm. - DIP joint flexion

Flexor carpi ulnaris

Adductor pollicis

Long thoracic nerve damage

Very superficial → fairly common injury

Clinical Presentation: medial border of the scapula moves laterally and posteriorly away from the thoracic wall resulting in a winged scapula bc serratus anterior no longer functioning

What nerves/vessels are we concerned about if there is a 1, 3 or 5 fracture?

1- axillary nerve and anterior/posterior circumflex humeral arteries

3- ulnar nerve

5- radial nerve and deep brachial artery

What happens with an axillary nerve injury?

Primary deficits: deltoid and teres minor

Clinical presentation: weakness in shoulder abduction and external rotation, atrophy of the deltoid, decreased sensation over the posterior/lateral shoulder

What happens with a radial nerve injury?

Clinical presentation: wrist drop, sensory deficits along posterior arm, dorsal hand, and thumb, inability to extend fingers (MCP Joints), inability to extend of abduct thumb, weakened grip strength

What happens with a musculocutaneous nerve injury?

Clinical presentation: impaired elbow flexion and forearm supination bc biceps brachii, brachialis, and coracobrachialis all affected

What happens with a median nerve injury above the elbow?

Hand of Benediction/ Pope’s Blessing

-when asked to form a fist, only digits 4 and 5 will flex (thumb and digits 2 and 3 will stay extended); weakened pronation; impaired flexion of wrist and sensory deficits to digits 1-3

Primary deficits:

-Thenar mm. (except adductor pollicis)

-All FDS

-Lateral 2 FDP mm.

-Flexor pollicis longus

-Flexor carpi radialis

-Pronator teres and pronator quadratus

What happens with a median nerve injury in the carpal tunnel?

Clinical presentation:

-thenar muscle wasting; tingling and pain in lateral 3.5 digits; difficulty with grasp reflex; possible median claw (injury to lateral lumbricals)

Primary deficits:

-Thenar mm. (except adductor pollicis); flexor pollicis brevis (superficial head), abductor pollicis brevis and opponens pollicis brevis; weakness upon flexion, abduction, and opposition of the thumb

What happens with a proximal ulnar nerve injury?

Clinical Presentation:

-weakened hand opening and grip strength; weakened grasp and pinch responses; “OK gesture” - weakened flexion of digit 4 and 5 when making a fist

Primary Deficits:

-weakened wrist flexion and adduction; weakened flexor digitorum profundus (medial part); paralysis of hypothenar mm., interossei, medial 2 lumbricals; sensory loss along ulnar distribution

What happens with a distal ulnar nerve injury?

Clinical Presentation: Ulnar claw hand deformity - hyperextension of the MCP joint bc of the unopposed extensors and flexed IP joints due to unopposed flexors in digits 4 and 5

Primary Deficits: paralysis of hypothenar mm., interossei, medial 2 lumbricals, flexor pollicis brevis (deep head), adductor pollicis; sensory loss along ulnar distribution

Ulnar Claw

Ulnar nerve lesion at wrist

Can see at rest

Digits 4 and 5 affected

Lumbricals to digits 4 and 5 are paralyzed

Hand of Benediction/ Pope’s Blessing

Median nerve lesion at elbow

See when attempting to make a fist but cannot flex digits 2 and 3

Digits 2 and 3 affected

Lumbricals and flexor digitorum profundus tendons to digits 2 and 3 paralyzed

What indicates an ulnar nerve palsy?

Positive Froment’s Sign with thumb interphalangeal joint flexion to compensate for paralysis of adductor pollicis muscle

What are you looking for with an XR?

Fx

Dislocation

Joint spaces/ edema/ arthritis

Lytic lesions

Foreign bodies

Basic hardware positioning

What are you looking for with a CT?

Occult fx, osteomyelitis, boney tumors, soft tissue lesions/ infections

Assessment of fx union/ osseous bridging (postop/ assess healing)

Evaluation of hardware integrity and loosening

Improved detail of boney lesions

CTA for arterial occlusion

CT with IV contrast for better detail of soft tissue masses, abscess, infection

What are you looking for with an MRI?

Soft tissue

Occult fx, bone contusions

Rotator cuff pathology, labral/ capsular injury

Muscle/ tendon tears, cartilage injury

Osseous and soft tissue neoplasm

Discerning infections

Ideal for joints

What are you looking for with nuclear medicine?

Both planar and cross sectional imaging

Increased bone turnover

Osteomyelitis

Malignancy

Avascular necrosis

PET (+CT and MRI) essential in diagnosing and staging malignancies

What are you looking for with ultrasound?

Tendon injuries

Fluid collections

Joint effusion

Procedural guidance

Nerve impingement assessment

Types of incomplete fxs

Torus/ Buckle fx

Greenstick - does not go through boney cortex

Distracted vs Overriding vs Comminuted

Distracted fx - transverse with space between

Overriding - transverse with shortening and overlapping

Comminuted - busted/burst; many pieces