Radiology 2B Week 9

What is the most common skeletal injury of birth and childhood?

Clavicle fracture

What are the most common shoulder injuries from age 20-40?

shoulder dislocation

AC joint separation

clavicle fractures

What are the most common shoulder injuries in the elderly?

shoulder dislocation

humerus surgical neck fracture

What are the radiographic projections of the shoulder?

AP internal rotation and external rotation

Baby arm (abduction view)

Grashey

Scapular Y

(also AC, scapula, and clavicle)

What factors make clavicle fracture difficult to identify?

S-shape

overlap with upper rib cage

What tilt of the x-ray tube is needed to evaluate clavicle?

15 degrees cephalic

What % of all fractures are clavicle fractures?

15%

What % of shoulder fractures are clavicle fractures?

44%

What gender is more commonly affected by clavicle fracture?

Male

What part of the clavicle is most commonly fractured?

Middle clavicle (75-80%)

What part of the clavicle will be displaced superiorly in the event of a middle clavicle fracture due to action of the SCM?

Medial fragment

What ligament is often injured in lateral clavicle fracture?

CC ligament

What % of clavicle fractures heal without complication?

95%

What are the potential complications of clavicle fracture?

Neurovascular damage

Non-union

Osteoarthritis of acromioclavicular joint

What is the diagnostic criteria for non-union of the clavicle?

Lack of callus within 6 weeks and gap is > 1.5 cm

What structures can be damaged by clavicle fracture?

subclavian artery and vein

brachial sympathetic chain

What is the term for resorption of the distal segment of the clavicle following injury?

Post-traumatic osteolysis of the distal clavicle

What demographic is osteolysis of the distal clavicle common in?

Weightlifters

What is the shape of an osteolysed distal clavicle?

Frayed

irregular

Cup

T or F: Scapula fracture indicates a minor trauma

False (severe trauma)

What views are used to evaluate scapula fracture?

Axillary view

A-P scapula

True lateral view

What is the AKA of true lateral view of the scapula?

Y view

What is the Y view used to evaluate in scapula fracture?

Glenoid fracture

What part of the scapula is usually fractured?

Body and neck (80%)

What is the AKA of greater tuberosity avulsion fracture?

Flap Fracture

Hidden fracture

When is flap fracture occult?

When non-displaced

What injury is greater tuberosity avulsion commonly associated with?

Anterior dislocation

What is the best view for visualizing greater tuberosity avulsion?

External rotation

What does displacement greater than 1 cm in greater tuberosity avulsion indicate?

Rotator cuff tear

What fracture is usually necessary for a lesser tuberosity fracture to occur?

Proximal humeral fracture

T or F: the lesser tuberosity is vulnerable to isolated fractures

False

What is the most common site for humeral fracture?

Surgical neck

What is the narrowest part of the humerus?

Surgical neck

What direction is the distal shaft displaced in a surgical neck fracture due to the action of the pectorals muscles?

Anterior and medial

What structures may be damaged by surgical neck fracture?

Axillary nerve

Axillary artery

What is the most common dislocation of the humerus?

Anterior (95%)

What are the 3 types of anterior glenohumeral dislocation?

Subglenoid

subcoracoid (MC)

subclavicular

What is the most common type of anterior humeral dislocation?

Subcoracoid

What is the MOI of anterior humeral dislocation?

Forceful abduction and external rotation

What are the potential complications of anterior humeral dislocation?

Hills-sachs lesion (60%)

HAGL (15%)

Bankart lesion

What does HAGL stand for?

humeral avulsion of the glenohumeral ligament

T or F: Anterior humerus dislocation recurrence is more common in older patients

False (more common in young patients)

What is the most commonly missed traumatic injury in the emergency room?

Posterior humeral dislocation

What are most common mechanisms of posterior humeral dislocation?

epileptic convulsion

electric shock

extreme trauma (triple E)

What are the radiographic signs of posterior humeral dislocation?

Widened joint space

double articular surface

lack of humeral head

glenoid fossa overlap

lack of close contact at anterior joint margin

cystic appearance of the head

superior displacement

What is the name sign for > 6mm widened joint space in posterior humeral dislocation?

Rim sign

What is the name sign for double articular surface due to reverse hill-sachs lesion in posterior humeral dislocation?

Trough line sign

What is the term for loss of glenoid fossa overlap in posterior humeral dislocation?

loss of half-moon shape

What is the name sign for lack of close contact of at the anterior joint margin in posterior humeral dislocation?

Vacant glenoid sign

What is the name sign for the cystic appearance of the humeral head in posterior humeral dislocation?

tennis racquet sign/light bulb sign

What is the AKA of inferior dislocation of the humerus?

Luxatio erecta

What injury causes inferior dislocation of the humerus?

Severe hyperabduction trauma

What can cause a superior dislocation of the humerus?

rotator cuff tear

What % of all shoulder injuries are AC joint separation?

10%

What gender is more affected by AC separation?

Male (5x)

What is the most common MOI of AC joint separation?

direct blow to acromion with abducted shoulder

What system is used to classify AC joint separation?

Rockwood classification system

What are the standard views of the aC joint?

AP (bilateral) weighted and non-weighted

What are the additional views of the AC joint?

AP with 10-15 degrees cephalic angulation

Lateral

Axial

What is a Rockwood type 1?

Sprained AC ligaments, intact CC ligament

What is the radiographic finding of a Rockwood 1?

Normal

What is necessary to visualize damage in a Rockwood 1?

MRI

What is a Rockwood type 2?

Ruptured AC ligaments, sprained CC ligament

What value of widening is diagnostic for a Rockwood 2?

Greater than 6 mm in females and 7 mm in males is abnormal

Or greater than 2 mm compared to uninjured side

How far superior is the clavicle displaced in a Rockwood 2?

50%

T or F: Weighted views will decreased the upward displacement of the clavicle

False

What is a Rockwood Type 3?

Clavicle dislocation with rupture of AC ligaments and CC ligament

(upward dislocation of the clavicle)

What distance of upward displacement is diagnostic for a Rockwood 3?

Greater than the width of the acromion

What is the normal width of the CC interspace?

12 mm (widened in rockwood 3)

What is a Rockwood type 4?

Type 3 with posterior dislocation

What is a Rockwood type 5?

Type 3 with incredible superior dislocation

What is a Rockwood type 6?

Type 3 with anterior/inferior dislocation

What is the AKA of + fat pad sign in the elbow?

Sail sign

What is the density of sail sign?

Water density

What causes sail sign?

Joint capsule effusion (usually due to trauma)

What does sail sign indicate?

Elbow injury (radial head fracture in adults, supracondylar in children)

T or F: Posterior fat pad visualization is more sensitive for trauma than anterior sail sign

True

What is the most common fracture of the elbow in children?

Supracondylar humeral fracture (60%)

What is the normal direction of displacement of supracondylar fracture fragment?

Posterior

What are the signs of supracondylar fracture?

abnormal anterior humeral line

positive sail sign

What is the normal finding of anterior humeral line?

Intersection of the middle third of the capitellum

What is the most common elbow fracture in adults?

Radial head fracture

What is the term for vertical fracture through the top of the radial head?

Chisel fracture

What is usually positive for radial fracture?

+ Fat Pad

What views should be used to identify radial head fracture?

oblique views

What is the most common site of radial neck fracture?

At the junction of head and neck (not the neck and shaft)

What is the term for fracture of the proximal ulnar shaft?

Monteggia fracture dislocation

What dislocation is associated with Monteggia fracture dislocation?

Radial head dislocation

What type of fracture is involved in Monteggia fracture dislocation in children?

Greenstick

What is the term for Fracture of the distal ⅓ of the radius with dislocation of the distal ulna?

Galleazi fracture dislocation

What are the AKAs of Galleazi fracture dislocation?

piedmont fracture

reverse monteggia fracture

T or F: Ulna dislocation has high probability of non-union

False (it often self-reduces)

What is the mnemonic for monteggia andgalleazi fracture dislocation?

MUGR (mugger)

Monteggia = proximal ulnar fracture, radial dislocation

Galleazi = radius fracture, radial dislocation

What is the term for fracture of the distal ulnar shaft from raising an arm to protect head during assault?

Nightstick / Parry fracture