The vertebral column, also called the spinal column, in vertebrates is composed of the bones, called the vertebrae, that go from the neck to the tail. The vertebrae are further differentiated into the caudal vertebrae (the bones in the tail), the sacral vertebra (often joined together to make the sacrum, which connects with the pelvic girdle), the lumbar vertebrae (in the lower back); the thoracic vertebrae (in the chest), and the cervical vertebrae (in the neck). In higher vertebrates, each vertebra has a centrum that is topped by a Y-shaped arch. The centrum and arch go around an opening, and the spinal cord goes through this opening. Each centrum is separated by the surrounding centrums by cartilage known as intervertebral disks. Vertebrae in the lower vertebrates are different and often have more complexity. The number of curves in the column varies by animal. Quadrupeds have one curve, though in humans there is also the sacral curve (which helps the sacra support the abdomen), the anterior cervical curve (to help raise the head), and the anterior lumbar curve (which forms as children walk and sit).
The function of the vertebral column is to protect the spinal cord. In addition, many muscles and other parts of the skeleton, such as the pectoral and pelvic girdles, are attached to the column. It also allows animals such as humans to transmit their weight while walking or standing.