The Classic: The Iliac Apophysis: An Invaluable Sign in the Management of Scoliosis

This Classic article is a reprint of the original work by Joseph C. Risser, The Iliac Apophysis: An Invaluable Sign in the Management of Scoliosis. An accompanying biographical sketch of Joseph C. Risser, MD is available at DOI 10.1007/s11999-009-1095-0. The Classic Article is 1958 by Lippincott Williams & Wilkins and is reprinted with permission from Risser JC. The iliac apophysis: an invaluable sign in the management of scoliosis. Clin Orthop Relat Res. 1958; 11:111–119. The Association of Bone and Joint Surgeons1 2009 Richard A. Brand MD (&) Clinical Orthopaedics and Related Research, 1600 Spruce Street, Philadelphia, PA 19103, USA e-mail: [email protected] Growth and completion of growth of the body is best shown by development of the bone growth centers, epiphyses and apophyses. The ossification of the carpal bones have long been used to indicate the bone age of a child. In infancy the time of femoral head ossification is also used to determine age. A delay in development usually is associated with a delay in metabolism. The last ossification centers to appear and develop are the iliac crest apophysis and, finally, the apophysis of the ischial tuberosity. The latter is smaller, more difficult to visualize in roentgenogram and thus is of little significance, whereas the iliac apophysis is plainly visible and has a rather long time element in its development. An apophysis is a growing center which, as its name indicates, grows (physis) upon (apo) the mother bone. It differs from the epiphysis in that with the development of the ossification center all growth is completed. Coincident with the development of the excursion of ossification of the iliac apophysis across the iliac crest, the vertebral growth plates are completed, and spinal growth is finished. It is difficult to visualize the vertebral body growth plates and determine growth completion. Because of an almost simultaneous development of the iliac apophysis and the vertebral growth plates, vertebral growth completion can be determined by observation of the development of the iliac apophysis. In the anteroposterior roentgenographic view of the pelvis, the iliac apophysis appears laterally and anteriorly on the crest of the ilium as an ossification center. This is termed capping (Fig. 1). With continued growth it develops posteriorly in its excursion of ossification across the iliac crest to dip down to contact the ilium medially at its junction near the sacrum. This is considered to be attached or completed (Fig. 2). When this completed ossification occurs, vertebral growth can be considered to be complete. Closure of the line between the apophysis and the ilium has no vertebral growth significance. Two or 3 years may be required for its closure. The average time for completion of the iliac apophysis to its medial and posterior attachment is about 1 year. The shortest lime was 7 months; the longest. 3 years (Fig. 3). The iliac apophysis may develop in fragments. After the usual capping or the appearance of ossification anteriorly and laterally on the iliac crest, further development may occur posteriorly, leaving a space, or gap, to be filled in later. 123 Clin Orthop Relat Res (2010) 468:646–653 DOI 10.1007/s11999-009-1096-z