We describe the case of a 13-year-old patient with a left wrist physeal fracture of the ulna and radius. X-Ray showed a Salter-Harris type II injury of the radius, and CT and MRI identified the following: type II epiphysiolysis of the radius with a metaphyseal wedge and type IV fracture of the ulna, with interposition in the focus of the fracture of the extensor carpi ulnaris tendon, as well as a tear in the central area of the triangular fibrocartilage complex. All these injuries were checked intraoperatively during open reduction. We believe that this clinical case illustrates the importance of carefully assessing physeal wrist injuries when they occur, especially in those cases involving the ulna and the radius. Diagnostic methods such as CT and MRI scans are indispensable for through evaluation and treatment of the injury.