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 main function of the thoracic spine is to hold the rib cage and protect the heart and lungs. The twelve thoracic vertebrae are numbered T1 to T12.

The main function of the lumbar spine is to bear the weight of the body. The five lumbar vertebrae are numbered L1 to L5.

The main function of the sacrum is to connect the spine to the hip bones (iliac). There are five sacral vertebrae, which are fused together. Together with the iliac bones, they form a ring called the pelvic girdle.

The four fused bones of the coccyx or tailbone provide attachment for ligaments and muscles of the pelvic floor.

While vertebrae have unique regional features, every vertebra has three functional parts. The spine is made of 33 individual bones stacked one on top of the other.