In brief: The Risser classification: a classic tool for the clinician treating adolescent idiopathic scoliosis.

Joseph C. Risser first described what now is called the Risser sign in 1958 [17]. Risser observed that the state of ossification of the iliac apophysis was associated with the state of a patient’s spinal skeletal maturity, a critical piece of information in the management of adolescent scoliosis [17]. His findings developed from work he did with Ferguson in 1936, which showed growth of the spinal column and progression of scoliosis were more rapid in children between 10 and 15 years old than in children between 5 and 10 years [18]. However, the difficulty of evaluating the vertebral growth plates drove him to look for a surrogate that could indicate vertebral growth potential. Risser found the completed excursion and ossification of the iliac apophysis were generally concurrent with that of the vertebral growth plates, and so he concluded, ‘‘the attachment of the iliac apophysis has proved to be an excellent physiologic sign to indicate the completion of the vertebral growth’’ [17]. Purpose