The Shoulder Flashcards
What are the four joints of the shoulder?
- Glenohumeral
- Acromioclavicular
- Sternoclavicular
- Scapulothoracic (functional?)
List 3 factors that cause shoulder instability
- Shallow glenoid
- Loose capsule
- Ligamentous laxity
Which is the most commonly dislocated joint in the body and why?
GH joint - stability is sacrificed for motion
List three complications of a shoulder dislocation - which is the most common?
- Rotator cuff/capsular tear
- Injury to axillary nerve/artery, brachial plexus
- Recurrent/unreduced dislocation (most common)
What is the mechanism of injury in an anterior shoulder dislocation? (2)
- Abducted arm is ER/hyperextended
2. Blow to posterior shoulder
What signs are/could be present in an anterior shoulder dislocation? (5)
- Inability to IR
- Positive apprehension test
- Positive relocation test
- Positive sulcus sign
- Neurovascular findings (axillary nerve - sensory patch over deltoid and deltoid contraction and musculocutaneous nerve - sensory patch on lateral forearm and biceps contraction)
What is a positive apprehension test?
Patient looks apprehensive with gentle shoulder abduction and external rotation to 90 degrees since humeral head is pushed anteriorly and recreates feeling of anterior dislocation (possible sign in anterior shoulder dislocation)
What is a positive relocation test?
Posteriorly directed force applied during the apprehension test relieves apprehension since anterior subluxation is prevented (possible sign in anterior shoulder dislocation)
What is the positive sulcus sign?
Presence of a subacromial indentation with distal traction on humerus indicates inferior shoulder instability (possible sign in anterior shoulder dislocation)
How would you investigate an anterior shoulder dislocation?
X-ray - AP, trans-scapular, axillary
List 4 radiographic findings would you find in an anterior shoulder dislocation
- X-ray axillary view: humeral head is anterior
- X-ray transcapular/scapular ‘Y’ view: humeral head is anterior to the Mercedes-Benz sign
- +/- Hill-Sachs lesion: compression fracture of posterior humeral head due to forceful impaction of anterioly dislocated humeral head against the glenoid rim
- +/- bony Bankart lesion: avulsion of the anterior glenoid labrum (with attached bone fragments)
What is a Hill-Sachs lesion?
compression fracture of posterior humeral head due to forceful impaction of anterioly dislocated humeral head against the glenoid rim
What is a Bankart lesion?
avulsion of the anterior glenoid labrum (with attached bone fragments)
How is an anterior shoulder dislocation managed?(4)
- Closed reduction with IV sedation and muscle relaxation
- Obtain post-reduction X-rays
- Check post-reduction NVS
- Sling x 3 weeks (avoid abduction and external rotation) followed by shoulder rehabilitation
What is the difference between joint laxity and joint instability?
Joint laxity - degree of translation in the GH joint which falls within a physiological range and which is asymptomatic
Instability - abnormal symptomatic motion - pain, subluxation or dislocation