Shoulder conditions Flashcards
Why is the shoulder joint prone to dislocation?
Because it’s very mobile but not as stable
In what direction does the humeral head usually move with a shoulder joint dislocation? Why?
Downwards
Because the coracoacromial arch and rotator cuff muscles prevent it dislocating upwards
and joint capsule is weakest inferiorly
What are the two types of shoulder joint dislocations?
Anterior
Posterior
How are anterior and posterior shoulder joint dislocations named?
Based on where the humeral head lies in relation to the infraglennoid tubercle
and long head of triceps
What are anterior shoulder joint dislocations caused by in terms of movement?
Excessive extension
Excessive lateral rotation
What direction is the humeral head forced in with an anterior shoulder joint dislocation?
Anteriorly and inferiorly
What effect do muscles have on the humeral head with a shoulder joint dislocation?
Flexor and adductor muscles pull it further anteriorly and superiorly
in a subcoracoid position
How does the patient present their arm with an anterior shoulder joint dislocation?
Slightly abducted
Laterally rotated
What nerve is at risk of damage in a shoulder joint dislocation?
Axillary nerve
What would damage to the axillary nerve result in?
Paralysis of deltoid, loss of shoulder abduction
Loss of sensation in upper lateral arm - regimental badge area
What are some other complications of a shoulder joint dislocation, apart from nerve injury?
Bankart lesion
Hill-sachs lesion
Axillary artery damage
Rotator cuff injury
Associated fracture
What is a Bankart lesion?
Anterior inferior glennoid labrum is stripped off
Joint capsule is ruptured
Injury to inferior glenohumeral ligament
What is a Hill-Sachs lesion?
Dentation of posterior lateral head of humerus
What causes a Hill-Sachs lesion?
Humeral head hitting the anterior glennoid
Hill-Sachs lesion is more common in first or recurrent shoulder joint dislocations? Why?
Recurrent
Have had more opportunities for damage
What may be fractured in a shoulder joint dislocation?
Head of humerus
Greater tubercle
Acromion, clavicle
What implications does tearing of the joint capsule have with a shoulder joint dislocation?
Increased risk of future dislocations
What causes a posterior shoulder joint dislocation?
Electric shock, seizures
What happens in a posterior shoulder joint dislocation?
Uncontrolled muscle contractions
Strength imbalance of rotator cuff muscles pulls humeral head out of place
What direction is the humeral head pulled in with a posterior shoulder joint dislocation?
Posteriorly and inferiorly
How does the patient present their arm with a posterior shoulder joint dislocation?
Adducted
Medially rotated
What are the signs of a posterior shoulder joint dislocation?
Square shoulder
Prominent coracoid process
What sign is seen on an X-ray with a posterior shoulder joint dislocation?
Lightbulb sign
Are anterior shoulder joint dislocations or posterior shoulder joint dislocations more common?
Anterior shoulder joint dislocations
Which part of the humerus is fractured in a surgical neck fracture?
Surgical neck of humerus duh
What causes a humeral neck fracture?
Direct blow to area
Fall outo an outstrecthed hand
force transmitted up the bones of the upper limb
What type of a fracture is a humeral neck fracture usually?
An impacted fracture - one bony fragment driven into spongey bone of another
Why do impacted fractures need less intervention?
Fracture is relatively stable
How does the patient present their arm with a humeral neck fracture?
Can move it with some pain
What neurovascular structures are at risk of damage with a humeral neck fracture?
Axillary nerve
Posterior circumflex humeral artery
What would damage to the axillary nerve result in?
Paralysis of deltoid muscle, loss of shoulder abduction
Loss of sensation in upper lateral arm - regimental badge area
What is shoulder impingement?
Rotator cuff tendons becoming compressed during shoulder movements
causes them to become inflamed which exacerbates the problem
What are the causes of shoulder impingement?
Anything that decreases the subacromial space
What is the subacromial space?
The space between the acromion and the humeral head
What are the symptoms and signs of shoulder impingement?
Painful arc
Positive result for Hawkin’s test
Movement affected
What can decrease the size of the subacromial space?
Bursitis - inflammation of subacromial bursa
Rotator cuff tendinitis - inflammation of rotator cuff tendons
Calcium deposits
Subacromial spurs
Varations in shape if acromion
What is the painful arc?
Pain when abducting arm 60-120 degrees approx
Why is pain experienced during the painful arc and Hawkin’s test with shoulder impingement?
Because the subacromial space becomes smaller
Compresses tendons further
What is Hawkin’s test?
Forward flexing shoulder 90degrees
Flexing elbow 90degrees
Medially rotating arm
What are you looking for in Hawkin’s test?
Pain
How is movement affected with shoulder impingement?
Loss of flexion and abduction
What is calcific supraspinatus tendinitis?
Deposition of calcium hydroxyapatite crystals on supraspinatus tendon
What do the calcium deposits cause?
Inflammation of supraspinatus tendon
Inflammation of subacromial bursa
What is the result of calcific supraspinatus tendinitis?
Shoulder impingement
What is a rotator cuff tear?
Tear in one or more tendons of the four rotator cuff muscles
What are the causes of a rotator cuff tear?
Shoulder impingement
Injuries e.g. shoulder joint dislocation
Degeneration with ageing
How do rotator cuff tears affect movement? Why?
Restricted movement - loss of muscle function
Painful movement - stretching of torn muscles
What are the types of rotator cuff tears? What do they each mean?
Partial thickness - fraying of intact tendon
Full thickness - hole in tendon, tendon detached from humerus
What is osteoarthritis?
Breakdown of articulating surfaces, cartilage and bone
What are the X-ray features of osteoarthritis?
Joint space narrowing
Osteophyte formation
Bone cysts
Subchondral sclerosis
What are osteophytes?
Bony spurs due to new bone formation
at margins of articulating surfaces
What are bone cysts?
Fluid filled sacs beneath articular cartilage
How does osteoarthritis affect joints?
Joints are inflamed - swollen, painful
Stiff
Deformed
Decreased range of motion (ROM)
What is subchondral sclerosis?
Increased bone density beneath articular cartilage
What is a mid-clavicular fracture?
Fracture in middle of clavicle
Where do mid-clavicular fractures usually occur? Why?
Between middle and lateral third
because it’s weaker here
What are the causes of a mid-clavicular fracture?
Falling directly on shoulder
Falling on an outstretched hand, force transmitted up upper limb bones
How does the medial fragment displace?
Superiorly
by sternocleidomastoid muscle
How does the lateral fragment displace?
Inferiorly by weight of deltoid and arm
Medially by pull of pectoralis major
Why is there shortening of the clavicle in a mid-clavicular fracture?
Due to the fragments over-riding each other
What does a damaged suprascapular nerve result in?
Loss of infraspinatus function, lateral rotation
Unopposed medial rotation - waiters tip
Which neurovascular structures are at risk of injury in a mid-clavicular artery?
Divisions and cords of brachial plexus
Suprascapular nerve
Subclavian artery
Which neruovascular structures are at most risk of injury in a mid-shaft humeral fracture?
Radial nerve
Profunda brachii artery
What is another complication of a mid-clavicular fracture, apart from neurovascular complications?
Pneumothorax
bony fragments may pierce parietal pleura, allowing air to enter, lung collapses
What are the consequences of damage to radial neve in a mid-shaft humeral fracture?
Loss of function on posterior compartment of forearm
loss of wrist extension, giving unopposed flexion
wrist drop
Loss of sensation in dorsal surface of lateral 3.5 fingers and area below them (not tips = median nerve)
Why is elbow extension maintained in a mid-shaft humeral fracture?
Radial nerve has already given off branches to the three heads of triceps brachii
Loss of function in anconeus but has only a minor role in elbow extension
What is the cubital tunnel?
Tunnel through which ulnar nerve passes into forearm
What forms the cubital tunnel?
Ligament joining medial epicondyle
to olecranon and posterior border of ulna
What are the symptoms of cubital tunnel syndrome?
Same as lesion of ulnar nerve at elbow, wrist
see wrist and hand conditions
What is cubital tunnel syndrome?
Compression of ulnar nerve at elbow
What is anaesthesia?
What is paraesthesia?
Anasthesia - numbness
Paraesthesia - tingling
