Shoulder Conditions Flashcards
What is the most common direction of shoulder dislocation?
What are 2 types? Which is most common and why
Anterior
Humerus head may lie;
- Anterior to glenoid fossa (More common due to pull of muscles)
- Antero-inferior to glenoid fossa
How does the arm appear in an Anterior dislocation
What are 2 mechanisms of anterior dislocation
Externally rotated
Slightly abducted
- Unexpected force pushes an abducted, laterally rotated arm posteriorly (Pushes shoulder backwards)
- Direct blow to posterior shoulder
What is a Bankart lesion/ Labral tear?
What can sometimes accompany this?
When part of glenoid labrum is torn off due to force of humeral head popping out of socket
Sometimes a small piece of bone can be torn off
What is a Hill-Sachs Lesion
A dent (Indentation fracture) in humeral head, caused by the tone of Infraspinatus and Teres Minor jamming the posterior humeral head into the anterior lip of the Glenoid Fossa
Posterior dislocations are less common than Anterior, but more than Inferior.
Identify 3 possible causes
- Violent muscle contractions (Seizure/ electrocution)
- Blow to anterior shoulder
- Arm is flexed across body and pushed posteriorly
How do patients with a Posterior Shoulder Dislocation present in 3 ways
- Arms are internally rotated and Adducted
- Flattening/ squaring of shoulder with a prominent Coracoid process
- Can’t be externally rotated
Why can a posterior shoulder dislocation be missed on an X-ray?
Name 2 ways one can be identified from an X-ray
Looks “In joint”
- Light bulb sign (Head looks more round, as arm is medially rotated)
- Increased glenohumeral space
How does a normal arm look in a lateral x-ray of shoulder, in reference to the Y-view
Name 3 injuries commonly associated with a Post. Dislocation
Normally, humeral head should be directly in line with bifurcation of the Y (Glenoid Fossa)
- Fractures
- Rotator cuff tears
- Hill-Sachs lesions
Describe the mechanism of Inferior Dislocation of the Shoulder
Forceful traction of arm when it is fully extended over the head
(Grasping an object overheard to break a fall- Hyperabduction)
What is the most common complication of shoulder dislocation (In any direction)
Recurrent dislocation (due to damage to stabilising tissues around the shoulder)
Damage to Axillary artery is uncommon in shoulder dislocations. Why are they more common in older people
Are nerve or arterial injuries more common? Which nerve is especially at risk?
Blood vessels are less elastic
Nerve injuries more common, especially Axillary nerve
Where may sensation be lost due to an Axillary Nerve injury
How well do most ppl with axillary nerve damage recover? Why?
Regimental Badge Area( Skin overlying the insertion of deltoid)
Most recover fully, as symptoms resolve when shoulder is reduced
When are significant fractures more likely to occur due to a shoulder dislocation?
Which 4 bones/ bone parts are most commonly affected
- Traumatic mechanim of injury
- First time dislocation
- Person is over 40
- Head of humerus
- Greater tubercle of humerus
- Clavicle
- Acromion
What is the most common part of the clavicle to be fractured?
What are 2 common mechanism of fracture?
How are most clavicle fractures treated?
The middle third (80%)
- Falls onto affected shoulder/ outstretched hand
- Treated conservatively with a sling
What are 6 occasions where a clavicle fracture should be treated surgically, rather than with a sling?
- Complete displacement (Bone ends cannot unite)
- Severe displacement (Tenting of skin, risk of puncture)
- Open fractures (Break in skin)
- Neurovascular compromise
- Interposed muscle
- Floating shoulder
Explain 3 outcomes of position of arm and clavicular fragment in a displaced mid-clavicular fracture?
- Medial segment elevated by Sternocleiodomastoid muscle
- Shoulder drops, as trapezius is unable to hold the lateral segment up against weight of upper limb
- Arm pulled medially by Pec Major (Adduction)
What is a rotator cuff tear
Which muscle tendon is most commonly torn, where?
Tear of 1/ more of the tendons of the 4 rotator cuff muscles
Supraspinatus tendon, at insertion into greater tubercle
Are rotator cuff tears mainly acute or chronic?
Can be acute (Dislocation), but mostly chronic due to extended used + other factors (Poor biomechanics/ muscle imbalance)
What’s the most common cause of a rotator cuff tear and why?
Age related degeneration, as blood supply to tendons decreases so reduced healing
The main theory behind rotator cuff tears is the Degenerative-microtrauma model.
Explain this
Age related tendon degeneration+ chronic micro trauma= Partial tendon tears-> Full tendon tears
Inflammation + oxidative stress-> Tenocyte apoptosis-> Further degeneration
What does a rotator cuff tear i 1 shoulder signal
Signals a tear in the other arm
Rotator cuff tears are usually asymptomatic.
Name 5 symptoms
Which is most common
- Anterolateral shoulder pain, radiating down arm (MOST COMMON)
- Shoulder pain when leaning on elbow and pushing downwards
- Shoulder pain when reaching forwards
- Pain restricted movement above horizontal position
- Weakness of arm abduction
What is Impingement syndrome?
When do you get symptoms?
Name 4
When Supraspintous tendon impinges on the Coraco-acromial arch, leading to inflammation/ irritation
When shoulder is abducted/ flexed;
- Dull (Rather than sharp) pain
- Weakness
- Reduced range of motion
- Grinding/ popping sensation of shoulder
In Impingment syndrome, what is the Painful Arc?
How is this syndrome treated
Pain, during 60-120 degrees of abduction
Treat the underlying cause
