A vertebra is one of the small, bony segments that make up the spine, also known as the vertebral column. Each vertebra has a central hole that forms the spinal canal, which houses the spinal cord. The vertebrae are stacked on top of each other, providing support and flexibility to the back while protecting the spinal cord. There are different types of vertebrae, categorized by their location: cervical (neck), thoracic (mid-back), and lumbar (lower back). Each type has a unique shape and function, contributing to the overall structure and movement of the human body.