Because of the location of those structures, it is hard to tell which structure actually hurts. This is a logical assumption, however it doesn't have to be true in the case of back pain. A person who sees a back specialist may get an x-ray on the first visit. In the event of neurological problems such as weakness, paralysis or loss of bladder control, an x-ray as well and an MRI or myelogram may be ordered. A disc is a large structure made of cartilage.
Most people think of the disc as a shock absorber, shaped like a jelly doughnut.
The disc functions more like a universal joint. The disc plays a large role in spinal stability and shares this mechanical load with the facet joints and the surrounding soft tissues. People who have pain in their extremities may improve with conservative or aggressive conservative care. The vast majority of people with a disc herniation will improve with time and will not need surgery. Anyone with a worsening set of symptoms, i.e. increasing pain, weakness, paralysis, loss of bladder or bowel control, poor coordination of the hands, or an unsteady gait, need urgent, if not emergent, evaluation by a spine surgeon.