Disc Bulge. A. Axial and B. Sagittal T2-weighted images reveal a focal right-central disc bulge at L4-5 that slightly indents the thecal sac and extends into the right nerve root canal (white arrow on A, black arrow on B). A more focal protrusion and associated annular tear is present at L5-S1 (white arrow on B). While degenerative changes such as disc bulges are extremely prevalent, the only degenerative feature associated with LBP is spinal stenosis. While disc herniations such as protrusions, extrusions, and sequestrations are more likely to result in direct nerve compression and chemical radiculitis resulting in lower extremity symptoms, they occur less frequently in elderly patients. (Images courtesy of Brian A. Howard, Charlotte, NC).