PURPOSE: The accessory bones around the elbow are very rare variant structures, present in approximately 0.7% of cases. They can cause diagnostic problems and can be mistaken for pathological structures, especially when pain and limitation of elbow movements are present and a trauma can be traced in the patient's history. They are of different nature, either presenting within muscle tendons as sesamoids (brachialis and triceps brachii muscles) or presenting intra-articularly probably as separated or accessory ossification centres. The least common is the os supratrochleare anterius. METHODS: We present a case of a young male, featuring chronic blocking and 20° limited flexion of his right elbow, which bothered him during his occupation as a locksmith. In history, he suffered minor trauma to the elbow 20 years ago. X-ray and CT showed a large ossicle in the coronoid fossa of the humerus. RESULTS: The ossicle was surgically extracted in small pieces. The patient left satisfied with no mention of complaints. CONCLUSION: The os supratrochleare anterius is a very rare accessory bone of the elbow, located in the coronoid fossa of the humerus which can mimic many pathological states, and limit movements and causing pain around the elbow.

Center for Endoscopic Clinical and Applied Anatomy 2nd Faculty of Medicine Charles University Prague Czech Republic

Department of Anatomy 2nd Faculty of Medicine Charles University 5 Úvalu 84 Prague 5 150 06 Czech Republic

Department of Health Care Studies College of Polytechnics Jihlava Czech Republic

Department of Histology and Embryology 3rd Faculty of Medicine Charles University Prague Czech Republic

Department of Trauma Surgery Faculty of Health Studies J E Purkyne University Krajska zdravotni Masaryk Hospital Usti nad Labem Czech Republic

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