How Your Spine Works

Between the Vertebrae — The Intervertebral Disc

Discs Act as Cushions

Between each pair of vertebrae sits an intervertebral disc — a cushion made of cartilage.

Structure of an intervertebral disc showing nucleus pulposus and annulus fibrosus

Each disc has a nucleus pulposus — a jelly-like center — surrounded by the annulus fibrosus, a tough outer ring of fibers.

Think of it this way: A disc is like a jelly doughnut:

  • The tough outer shell = the doughnut (annulus fibrosus)
  • The soft center = the jelly filling (nucleus pulposus)

Thanks to these discs, your spine can bend in all directions and absorb shocks from walking, running, and daily activities.