The spinous process: the forgotten appendage.

The spinous process (SP) is often neglected in the radiologic examination of the spine. Proper coning decreases scattered radiation to the SP's in the lateral view. Lateral zonography (thick cut tomography) is occasionally needed in the thoracic region. In the anteroposterior view paying attention to alignment of the SP's and the distance between them will help in the diagnosis of fracture and/or dislocation. Examination of the spinolaminal line (i.e. the line joining the base of the SP's) on the lateral view is also important in looking for the alignment of the vertebra in trauma. Local absence of indistinctiveness of the spinolaminal line may be recognized in spina bifida or when an osteolytic process involves the cortex in this area. The SP itself is involved, with or without the remainder of the vertebra, in metastatic or primary carcinoma, in trauma, rheumatoid arthritis and Paget's disease and in primary benign tumors.