Abnormal clavicle morphology Distal clavicular osteolysis 2026-02-26T07:36:12Z Degeneration and resorption of the distal part of the clavicle near the acromioclavicular (AC) joint. Distal clavicular osteolysis (DCO) is an atypical injury occurring most often in athletes and weight lifters, specifically those who perform repetitive overhead movements. DCO results from repetitive excess load to the AC joint, typically through horizontal adduction, adduction, internal rotation, and forward/lateral flexion of the shoulder, such as bench pressing or overhead lifting. Imaging (AP clavicle and/or Zanca view of the AC joint) of DCO often demonstrates microcysts, loss of subchondral bone detail, and osteolysis of the distal clavicle.