AC joint to Elbow Flashcards
What are the 3 grades for an AC joint injury?
Grade I = mild sprain
Grade II = moderate sprain
Grade III = severe sprain
What is the most common mechanism of injury for an AC joint injury?
Landing on top of shoulder
Which AC joint sprain grade appears radiographically normal?
Grade I
A Grade III AC joint sprain involves the tearing of which two ligaments?
Acromioclavicular and coracoclavicular ligaments
A Grade II AC joint sprain involves the tearing of which ligament?
Acromioclavicular
What is the normal range for the space at the distal end of the clavicle (AC joint)?
0-5mm
What is the normal range of the space between the clavicle and coracoid process?
0-11mm
What special X-ray view of the shoulder can help assess AC join separation?
Y-view
How is a severe AC joint sprain treated?
Screw through clavicle into coracoid process with resection of clavicle
What is the most common fracture in infants/kids?
Middle third clavicle
Which third of the clavicle is least likely to fracture?
Medial third
Posterior dislocation of which clavicular joint can be potentially life threatening and why?
Sternoclavicular; compression of great vessels
What anatomical structure is pulled up and which is pulled down following a clavicle fracture?
SCM pulled up, shoulder droops
How can callus formation following a clavicular fracture lead to a complication?
Neurovascular ocmpromise
Which artery is especially at risk of complication following a clavicle fracture?
Subclavian (also brachial plexus)
What is the name of the classifications system for humeral fractures?
Neer Classification
What is the most common direction for a shoulder dislocation?
Anterior (97%)
What is the most common type of anterior shoulder dislocation?
Subcoracoid
What are the three subcategories of anterior shoulder dislocations?
Subcoracoid, subglenoid, intrathoracic
The type of anterior shoulder dislocation is assessed relative to the position of which bone?
Resting place of humerus after dislocation
Does the humeral head usually move inferior or superior with an anterior shoulder dislocation?
Inferior
In which direction does the humeral head usually move with a posterior shoulder dislocation?
Either stays the same or superiorly
A Bankart lesion is associated with what injury?
Anterior shoulder dislocation
Where does the Bankart lesion occur?
Inferior aspect of the labrum (avulsion fracture)
What is the name of the injury that results from an anterior shoulder dislocation that is a cortical depression in the posterolateral head of the humerus results from forceful impaction of the head against the anterioinferior glenoid rim?
Hill-Sachs lesion (appears as “V” shape depression)
What is a flap fracture (type 4 Neer)?
Avulsion of the greater tuberosity by retraction of the rotate cuff
What are the 3 possible mechanisms of injury for a posterior shoulder dislocation?
1 direct blow to arm
2 electrical shock
3 convulsive seizures
What is the name of the sign that appears with a posterior shoulder dislocation that is analogous to the Hill-Sachs lesion of an anterior dislocation?
Trough sign
What is the different of location between the trough sign and Hill-Sachs lesion?
Trough sign = anterior medial surface
Hill-Sachs = posterolateral head
What is the name of the shoulder dislocation where the humerus is dislocated anteriorly and inferiorly with the arm hyperabducted and locked above the head?
Luxatio erecta
Why is a luxatio erecta dislocation particularly serious?
Increased potential for neurovascular issues
What four muscles make up the rotator cuff?
Supraspinatus, infraspinatus, teres minor, and subscapularis
Which muscle is most commonly injured in a rotator cuff injury?
Supraspinatus
What is unique about the anatomy of the subscapularis compared to the other rotator cuff muscles?
Subscapularis inserts on the lesser tuberosity instead
What is the location of the “critical zone” in reference to a rotator cuff injury?
1 cm proximal to supraspinatus insertion at greater tuberosity
Why is the critical zone called that?
Area of least vascularization aka most susceptible to tear
The acromiohumeral joint space is narrowed to how many millimeters with a rotator cuff tear seen on X-ray?
Less than 6mm
How does a rotator cuff injury change the acromion process?
Erosion of the inferior aspect
How does a rotator cuff injury change the greater tuberosity?
Flattening and atrophy
What is the best imaging procedure to asses for a rotator cuff tear?
MRI (soft tissues)
How does a rotator cuff tear appear on MRI?
Area of increased signal intensity (white) between the tendon (aka fluid disrupting continuity)
What is the name for a rotator cuff tear that doesn’t go completely through the tendon but is still visible upon MRI?
Intrasubstance tear