Several accessory bones can be found around the wrist, which may pose a diagnostic challenge. Hereby, we report a unique case of a traumatic fracture of an aberrant os styloideum in a 66-year-old male. The patient presented with a swollen dominant right hand and a hematoma on its anterior and posterior aspects, as a result of a fall on an outstretched hand. The diagnosis was based on a CT scan, which showed a fractured accessory bone between the distal portion of the capitate bone and the base of the third metacarpus. Due to its typical location, the ossicle was identified as os styloideum. The patient was treated conservatively and the symptoms subsided on a short forearm cast after 2 weeks. At a 12-month follow-up, no other episodes were declared. Strong anatomical knowledge and sharing of such cases is essential for proper diagnosis and treatment of this very rare condition.

Clinic of Trauma Surgery Masaryk Hospital Socialni pece 3316 12A 400 111 Usti nad Labem Czech Republic

Department of Anatomy 2nd Faculty of Medicine Charles University Prague Czech Republic

Orthopaedic and Hand Surgery Unit National Trauma Center and National Academy of Medical Sciences Kathmandu Nepal

Research Centre Faculty of Health Studies Jan Evangelista Purkyne University in Usti nad Labem Ústí nad Labem Czech Republic

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