Anatomy of Scoliosis

To understand scoliosis, which causes the spine to curve to the left or right, you first need to understand what a normal spine looks like. There are four regions in your spine:

• Cervical Spine: This is your neck, which begins at the base of your skull. It contains 7 small bones (vertebrae), which doctors label C1 to C7 (the 'C' means cervical). The numbers 1 to 7 indicate the level of the vertebrae. C1 is closest to the skull, while C7 is closest to the chest.
  
  
• Thoracic Spine: Your mid-back has 12 vertebrae that are labeled T1 to T12 (the 'T' means thoracic). Vertebrae in your thoracic spine connect to your ribs, making this part of your spine relatively stiff and stable. Your thoracic spine doesn't move as much as the other regions of your spine, like the cervical spine.
  
  
• Lumbar Spine: In your low back, you have 5 vertebrae that are labeled L1 to L5 (the 'L' means lumbar). These vertebrae are your largest and strongest vertebrae, responsible for carrying a lot of your body's weight. The lumbar vertebrae are also your last "true" vertebrae; down from this region, your vertebrae are fused. In fact, L5 may even be fused with part of your sacrum.
  
  
• Sacrum and Coccyx: The sacrum has 5 vertebrae that usually fuse by adulthood to form one bone; the coccyx-most commonly known as your tail bone-has 4 (but sometimes 5) fused vertebrae.

From behind, the normal spine appears straight. However, when viewed from the side, you'll see that the spine has both inward and outward curves. These curves help our back carry our weight and are also important for flexibility.

There are two types of curves in your spine: kyphosis and lordosis. You can see those from the side view. Kyphosis means the spine curves inward; lordosis means the spine curves outward. There are two kyphotic and two lordotic spinal curves in a normal spine. Your neck (cervical spine) and low back (lumbar spine) have a lordotic curve. Your mid back (thoracic spine) and pelvis (sacrum) have a kyphotic curve.

As you can probably tell from the basic curves of the spine, it's a complex structure. Your spine is made up of many parts. Your spinal column, also called your vertebral column, has 24 individual bones-those are your vertebrae. In between the vertebrae, you have intervertebral discs that act like pads or shock absorbers. Each disc is made up of a tire-like outer band (annulus fibrosus) and a gel-like inner substance (nucleus pulposus).

Together, the vertebrae and the discs provide a protective tunnel (spinal canal) for the spinal cord and spinal nerves. The spinal cord runs from the brain down through most of the spine. Nerves branch off the spinal cord at interval and exit through openings called the foramen. From there, nerves go to various parts of your body, helping you move and feel.

Besides the bones, discs, and nerves, your spine has muscles, ligaments, and blood vessels. Muscles are strands of tissues that act as the source of power for movement. Ligaments are the strong flexible bands of fibrous tissue that link the bones together. Tendons connect muscles to bones and discs. Blood vessels provide nourishment. These parts work together to help you move, and they also help stabilize your spine.