[Pelvic abnormalities affecting the statics of the vertebral column]

Of all the bony anomalies of the pelvis, unilateral developmental disturbances of the body of the iliac bone and the lateral parts of the os sacrum mainly affect the statics of the vertebral column. After a short description of the normal development of the os coxae and os sacrum, an attempt is made to systematize these anomalies and explain them from a developmental point of view. This is achieved by studying anatomical specimens and clinical cases. Primary disturbances concerning the growing of the cartilaginous epiphysis itself or secondary disturbances, which result from unilateral muscular palsy, can be responsible for retarded development of the body of the iliac bone. Unilateral dysplasia of the lateral part of the os sacrum could be based on disturbances of the precartilage. This is also thought to be the reason for asymmetrical formations of so-called transitional vertebrae.