Two patients with post-traumatic osteolysis of the distal end of the clavicle undergoing surgery 5 months and 22 months respectively after the initial trauma were evaluated histopathologically. The lysed zone was replaced by tissue of fibrous appearance, with little blood supply and non-inflammatory, the presence of which could be suspected by magnetic resonance. The synovial membrane, non-inflammatory but hypervascularised, participated in the process but did not appear to be directly responsible for the osteolysis. The osseous tissue of the patient, operated upon early, showed signs of osteoclastic resorption but there was neither stasis, vasodilatation nor signs of osteogenesis. These various findings suggest that post-traumatic osteolysis of the distal end of the clavicle does not result from local ischemic events. These appearances seem identical to those described in multifocal primary osteolysis, the cause of which also remains unknown.