Vertebras are the individual bones that collectively make up the vertebral column, or backbone, of humans and many animals. There are several synonyms for vertebras, including spinal bones, backbone segments, vertebral bodies, and spinal column bones. These terms are often used interchangeably to refer to the small, cylindrical bones that articulate with one another to allow for flexibility and movement of the spine. Other related terms may include intervertebral discs, which are the cushions of cartilage that provide shock absorption between the vertebras, and the spinal cord, which runs through the hollow center of the vertebrae.