What are the small bones that make up a backbone called?

The small bones that make up a backbone are called vertebrae. Together, they form the vertebral column, or spinal column, which supports the body and protects the spinal cord.

Most people have 33 vertebrae at birth, although several fuse during development. In adults, the column is usually described as having 24 movable vertebrae, followed by the fused sacrum and coccyx. These bones are grouped into cervical, thoracic, lumbar, sacral and coccygeal regions.

The vertebrae are not identical. The seven cervical vertebrae support the neck, the 12 thoracic vertebrae connect with the ribs, and the five lumbar vertebrae carry much of the body's weight. Between most movable vertebrae are flexible discs that cushion shocks and allow bending and twisting.

A common mix-up is calling the entire backbone a single bone. The backbone is a chain of vertebrae, while the spinal cord is the bundle of nerves running through the protected spinal canal.