The first effect demonstrated is fusion of the sacroiliac joints. The disease causes extensive calcification of the anterior longitudinal ligament of the spinal column. It is progressive, working up the vertebral column and creating a radiographic characteristic known as bamboo spine. Males are most often affected.

These hip dislocations are caused by conditions present at birth and may require frequent hip radiographs. 

The most common type of aseptic or ischemic necrosis. Lesions typically involve only one hip. The disease occurs predominantly in 5–10-year-old boys and a limp is usually the first clinical sign. Radiographs demonstrate a flattened femoral head that later can appear fragmented. 

The malignancy spreads to the bone via the circulatory system or lymphatic system or by direct invasion. Metastatic tumors of the bone are much more common than primary malignancies. Bones that contain red bone marrow are more common metastatic sites (spine, skull, ribs, pelvis, and femora).

Because of the closed ring structure of the pelvis, a severe blow or trauma to o e side of the pelvis may result in a fracture opposite from the site of primary trauma, thus requiring clear radiographic visualization of the entire pelvis. This type of trauma is referred to as a contrecoup injury. 

This condition usually occurs in 10–16-year-olds during rapid growth, when even minor trauma can precipitate its development. The epiphysis appears shorter and the epiphyseal plate wider with smaller margins.