Minimal process. Wear and tear can cause degeneration in the vertebral column, and cause discs to deteriorate. The supportive basket, nucleus fibrosis develops small tears. A bulge is minimal perhaps a few millimeters, and is clinically insignificant, but additional disc displacement such as protrusion or herniation may compress nerve or spinal cord.
MRI interpretation. On an MRI scan you see a lot of detail about the shape, hydration, small injury patterns and the amount of disc material that extends into the spinal canal. When the disc extends beyond the edge of the vertebral spine, whether due to anatomic variation or pathology, it can be described as "bulging". Bulging disc may be seen with or without pain.