Between each vertebral body of the spine are pads of fibrocartilage–based structures that provide support, flexibility, and minor load–sharing known as the intervertebral discs. These are primarily composed of two layers: (1) a soft, pulpy nucleus pulposus on the inside of the disc and (2) a surrounding firm structure known as the annulus fibrosus. A disruption of the normal architecture of these round discs can lead to a disc herniation or a protrusion of the inner nucleus pulposus, possibly applying pressure to the spinal cord or nerve root and resulting in radiating pain and specific locations of weakness.

MRI is the standard imaging modality for detecting disc pathology due to its advantage of lack of radiation, multiplanar imaging capability, excellent spinal soft–tissue contrast and precise localization of intervertebral discs changes.