Acromioclavicular joint injury: grade 4
Presentation
Driver of a motor car traveling at unknown speed collided head-on with another car; presented with pain in right shoulder.
Patient Data
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Grade IV Dislocation of the AC joint of right shoulder.
AP view of the shoulder demonstrates disruption of the AC joint and superior displacement of the lateral end of the clavicle.Axillary view of the shoulder demonstrates the posterior displacement of the lateral end of the clavicle which is usually through the Trapezius muscle.
Case Discussion
The case presented here is a type 4 acromioclavicular joint dislocation where the lateral end of the clavicle is displaced superiorly and posteriorly into or through the trapezius muscle.
Superior displacement of the lateral end of the clavicle signifies rupture of coracoclavicular ligaments, acromioclavicular joint capsule and deltopectoral fascia.