Tap any bone or disc on the model to see what it does and why it is sometimes operated on. Or press Play below for a quick challenge.
Pick the operation you had (or are recovering from), then use Before / After on the model. Levels shown are examples — real surgery is planned on each person's scans.
An adult spine usually has 33 vertebrae: 7 in the neck (Cervical), 12 in the upper and mid back (Thoracic), 5 in the lower back (Lumbar), then the sacrum (5 fused) and coccyx (tailbone, usually 3–5 fused)[S5][S28].
How names work: the letter is the region and the number counts down from the top, so C5 is the fifth neck bone and L4–L5 is the disc between the 4th and 5th lower-back bones. Spinal nerves are numbered a little differently — there are 8 pairs of neck nerves but only 7 neck vertebrae[S1].
Natural curves: neck and lower back curve inward (lordosis), upper back curves outward (kyphosis). Typical neck curve is about 20–40°, upper back about 20–50°, and the lower back averages around 60°[S8]. Between the bones, each disc acts as a cushion with a tough outer ring and a softer centre[S28].
The spinal cord carries messages between brain and body. In general, the higher the level of a cord injury, the more of the body can be affected: neck-level injuries can affect arms and legs (tetraplegia), while injuries in the chest, lower back or below affect the legs and trunk (paraplegia)[S23]. How complete the injury is matters as much as the level, and every person is assessed individually.
In US data on traumatic spinal cord injury, about 55% are neck-level, 35% thoracic and 10% lumbar[S22]. In adults the cord itself usually ends around L1; below that the canal holds a bundle of nerve roots called the cauda equina[S25].
Also from our family of sites: helplines.com.au · carercompass.org