The 33 vertebrae make up five distinct spine segments. Starting at the neck and going down toward your buttocks (rear end), these segments include:

• Cervical (neck): The top part of the spine has seven vertebrae (C1 to C7). These neck vertebrae allow you to turn, tilt and nod your head. The cervical spine makes an inward C-shape called a lordotic curve.

• Thoracic (middle back): The chest or thoracic part of the spine has 12 vertebrae (T1 to T12). The ribs attach to the thoracic spine. This section of the spine bends out slightly to make a backward C-shape called the kyphotic curve.

• Lumbar (lower back): Five vertebrae (L1 to L5) make up the lower part of the spine. Your lumbar spine supports the upper parts of the spine. It connects to the pelvis and bears most of your body’s weight, as well as the stress of lifting and carrying items. Many back problems occur in the lumbar spine. The lumbar spine bends inward to create a C-shaped lordotic curve.

• Sacrum: This triangle-shaped bone connects to the hips. The five sacral vertebrae (S1 to S5) fuse as a baby develops in the womb, which means they don’t move. The sacrum and hip bones form a ring called the pelvic girdle.

• Coccyx (tailbone): Four fused vertebrae make up this small piece of bone found at the bottom of the spine. Pelvic floor muscles and ligaments attach to the coccyx.