injuries generally occur through the zone of provisional calcification, a relatively weak area of the germinal growth plate that becomes even more susceptible to injury during periods of growth in adolescence (peak incidence at 11 to 12 years old) Most growth plate injuries occur in the upper limb, particularly in the radius and ulna Several classification systems have been described for physeal fractures The most widely used is that of Salter and Harris, who described five types of growth plate fractures, each having specific prognostic and treatment implications ( Fig 111.2 ) Salter –Harris type I fracture This fracture type is a separation of the metaphysis from the epiphysis through the zone of provisional calcification resulting in a widening of the physeal space Diagnosis may be challenging if displacement is minimal Radiographs may only show associated soft tissue swelling Type I fractures are generally benign, and growth disturbance is uncommon if near-anatomic reduction is achieved Exceptions include type I injuries of the proximal and distal femur and the proximal tibia, which are subject to premature physeal closure and posttraumatic growth arrest In general, when radiographic studies are negative, but physical examination findings are suggestive of a Salter–Harris type I injury (e.g., point tenderness over a growth plate), immobilization and a follow-up examination are essential Imaging showing periosteal reaction along the physis to 10 days after possible Salter– Harris fractures may help diagnose the occult injury