The spine is a masterpiece of engineering. The four curves of the spine and their varying shapes perfectly balance the two primary functions of our skeletal system: stability and mobility.
The spine is made up of four curves. The cervical spine is the topmost curve. It is comprised of seven vertebrae in the neck. Below it, the 12 thoracic vertebrae form the curve to which the ribs attach. The low back, or lumbar curve, is made up of five vertebrae, the largest bodied vertebrae of the spine. And the bottommost curve is comprised of five fused vertebrae in the sacrum followed by four fused vertebrae in the coccyx. This bottommost curve of the spine joins with the pelvis and serves as the back of the pelvic bowl.
The cervical and lumbar spines are concave curves, and the thoracic and sacral spines are convex curves. This spring-loaded design of alternating curves provides natural shock absorbing and helps us to maintain balance, as the curves can deepen or lengthen as needed as we maneuver through our day. In addition, the vertebrae in each curve of the spine have slight variations in shape to facilitate four primary actions. Here’s how this works as you flow through your yoga poses (asanas).