It is caused by severe upward and forward thrust by an indirect force from below with the arm commonly in adduction.
CLINICAL FEATURES :
•A clearly elevated shoulder with head felt over acromion, arm shortened.
•Arm adducted and very painful shoulder without movement.
•Associated fractures of acromion, acromioclavicular join, clavicle, coracoid or humeral tuberosities.
•Soft tissue damage especially of superior capsule and rotator cuff.
•Neurovascular involvement is common.
•Closed reduction and restoration of the damaged tissue.