- An abnormal curve of the lumbar spine is lordosis, also called sway back.
- An abnormal curve of the thoracic spine is kyphosis, also called hunchback.
- An abnormal curve from side-to-side is called scoliosis.
Your spine keeps your body standing upright! But your spine is not long and straight. It has CURVES, and it needs curves! The spine is made up of 33 individual bones (vertebrae) that interlock with each other to form the spinal column. The vertebrae are numbered and divided into regions: cervical, thoracic, lumbar, sacrum, and coccyx. Only the top 24 bones are moveable; the vertebrae of the sacrum and coccyx are fused. The vertebrae in each region have unique features that help them perform their main functions. Cervical (neck) – the main function of the cervical spine is to support the weight of the head. The seven cervical vertebrae are numbered C1 to C7. The neck has the greatest range of motion because of two specialized vertebrae that connect to the skull. The first vertebra (C1) is the ring-shaped atlas that connects directly to the skull. This joint allows for the nodding or “yes” motion of the head. The second vertebra (C2) is the peg-shaped axis, which has a projection called the odontoid, that the atlas pivots around. This joint allows for the side-to-side or “no” motion of the head. Thoracic (mid back) – the main function of the thoracic spine is to protect the heart and lungs. The twelve thoracic vertebrae are numbered T1 to T12. The range of motion in the thoracic spine is limited due to your ribs starting and ending on different halves of your body. (from the front to the back or vice versa). Lumbar (low back) – the main function of the lumbar spine is to bear the weight of the body. The five lumbar vertebrae are numbered L1 to L5. These vertebrae are much larger in size to absorb the stress of lifting and carrying heavy objects. Sacrum – the main function of the sacrum is to connect the spine to the pelvic bones. There are five sacral vertebrae, which are fused together. Together with the pelvic bones, they form a ring called the pelvic girdle. Coccyx region – the four fused bones of the coccyx or tailbone provide attachment for ligaments and muscles of the pelvic floor. Excess body weight, weak muscles, spine bones not moving correctly and other forces can pull at the spine’s alignment: