A mild broad-based disk protrusion is the extension of herniated disk material beyond the edges of the vertebral body apophyses, says the American Journal of Neuroradiology. The percentages are typically between 25 and 50 of the circumference of the disk itself.
A mild broad-based disk protrusion refers only to the single disk where the extended material occurs. It does not include other disks in the same area that are experiencing problems or are in need of treatment. If the extended material measures less than 25 percent of the disk circumference, it is termed a focal protrusion. When the extended herniated disk material exceeds 50 percent, it is a bulging disk, according to the American Journal of Neuroradiology.