•Inferior dislocation is rare.
•Dislocation occurs with the arm in nearly full abduction/elevation.
•The humeral head is levered out of its socket and pokes into the axilla & the arm remains fixed in abduction.
MECHANISM OF INJURY :
The injury is caused by a severe hyper abduction force.
• Shoulder in attitude of 110-160° hyperabduction, elbow fixed with forearm over the chest or behind the head.
• Head of humerus felt in axilla below and lateral to chest wall.
• Diffuse extreme pain around shoulder.
• Very common association of neurovascular complications commonly the axillary nerve and vessels
Severe soft tissue injuries
Avulsion of rotator cuff, capsule, pectoralis major
Fracture of greater tuberosity, inferior glenoid rim and acromion.
Inferior dislocation can usually be reduced by pulling upwards in the line of the abducted arm, with counter traction downwards over the top of the shoulder.
The arm is rested in a sling until pain subsides
Abduction is avoided for 3 weeks to allow the soft tissue to heal
If the humeral head is stuck in the soft tissues, open reduction is needed.