Anatomy and Physiology of Pediatric Bone CLINICAL PEARLS AND PITFALLS During periods of growth, the regions of the pediatric skeleton undergoing rapid metabolic activity are more susceptible to fracture Fracture remodeling in pediatric patients is robust and allows for more acceptable angulation at the time of casting, and less frequent operative repair than adult fractures Current Evidence Unique elements of the bony architecture in children include a thick and active periosteum, a physis (growth plate), and an epiphysis (secondary ossification center) ( Fig 111.1 ) Structurally, the bones of a child are much more porous and pliable than those of an adult As a result, overall bony strength is less, and the incidence of fractures is greater in children than in adults Moreover, ligaments have greater strength than the physes; thus, a child is more likely to suffer a fracture from an injury that, in a skeletally mature individual, would result in a sprain, ligamentous injury, or dislocation Unlike in adults, remodeling and anatomic fracture union for pediatric fractures is the expectation rather than the exception In general, significant remodeling can be anticipated both in younger children and when the fracture occurs in the metaphysis of growing bones The greatest degree of remodeling is anticipated with bony injuries occurring in the plane of motion of the adjacent joint In contrast, the injuries least likely to correct without intervention include those that occur in the diaphysis of long bones in adolescents, those with bowing greater than 10 degrees, and fractures with rotational malalignment In general, the goal is to obtain as near an anatomic reduction of the fracture fragments as possible in all age groups and not to rely on remodeling to align angulated fractures; however, relative guidelines for acceptable angulation by age are provided Physeal Fractures Salter–Harris type I injuries are frequently diagnosed clinically by point tenderness at the physis and may not be evident radiographically Selective use of radiographs of the contralateral extremity may help with diagnosing physeal injury An important complication of physeal fractures is growth disturbance, which may result in angular deformity, limb length discrepancy, and/or epiphyseal