Shoulder trauma Flashcards
What is the shoulder joint?
The gleno-humeral joint
What is the most common shoulder dislocation?
Anterior dislocation (95%)
- pushed infero-anteriorly
- tends to come to lie beneath coracoid process
How do anterior shoulder dislocations occur?
Excessive extension
Lateral rotation
What further damage can result specifically from an anterior shoulder dislocation?
Axillary nerve damage
- supplies teres minor and deltoid
- sensory defect in regimental badge area
Axiallary artery damage
=> absent pulses and ischaemia further down arm
What other shoulder dislocations can occur?
Posterior dislocation (4%)
Inferior dislocation (1%)
How do posterior shoulder dislocations occur?
Humerus rotates laterally => head faces anteriorly
What further damage can be caused with a shoulder dislocation?
Fibrous capsule/ligaments
Labrum (fibrocartilaginous rim of glenoid cavity)
=> deepens
Bankart’s lesion
Hill Sach’s lesion
What is Bankart’s lesion?
Stripping of anterior glenoid labrum and anterior capsule from neck of scapula
What is Hill-Sach’s lesion?
Bony defect in posterolateral part of head of humerus
Why is an acromio-clavicular dislocation rare?
Because of the strength of coraco-clavicular ligaments
- more likely to fracture a clavicle
What ligaments secure the AC joint?
AC ligament - weak
Coraco-clavicular ligament - very strong
What happens to the shoulder if the coraco-clavicular ligament is ruptured as a result of AC dislocation?
Shoulder drops since the scapula and humerus fall inferiorly away from clavicle
What may cause a fractured clavicle?
Fall on an outstretched arm
Fall on shoulder
Where exactly do clavicle fractures normally occur?
Medially to coraco-clavicular ligament due to ligament strength
What is the appearance of a fractured clavicle?
Shoulder drop
- lateral fragment no longer held up
Shortening of clavicle
- lateral fragment pull medially by arm adductors (pecs)
Elevation of medial fragment
- by sternocleidomastoid
What is Erb-Duchenne palsy?
Injury to superior part of brachial plexus (C5 and C6)
Resulting in “waiter’s tip position” of arm/hand
- mostly musculocutaneous nerve
What causes an Erb-Duchenne palsy?
Widening of gap between neck and shoulder
- being thrown from bike/horse onto shoulder
=> neck streched away from shoulder, avulsing upper roots - excessive stretching of neck in delivery of baby
What is a Klumpke palsy?
Injury to inferior parts of brachial plexus (C8 and T1)
Results in “claw hand”
- short muscles of hand affected
- mostly ulnar nerve
What causes a Klumpke palsy?
Limb pulled superiorly, widening gap between arm and lateral side of thorax
- holding on to tree trunk
- baby delivered by excessive pulling on arm and lateral side of thorax
