The vertebral column is comprised of 33 interconnected segments that create a flexible yet incredibly resilient structure, supporting the back through its full range of motion. This column also safeguards the spinal cord, which extends from the brain through the hollow central space. It consists of 7 cervical (C1-C7), 12 thoracic (T1-T12), 5 lumbar (L1-L5), 5 sacral (S1-S5), and 3 to 5 coccygeal vertebrae, each separated by intervertebral discs. The first cervical vertebra, called the atlas, supports the head and rotates around the odontoid process of the second cervical vertebra, known as the axis. The cervical vertebrae conclude where they meet the thoracic vertebrae. The seventh cervical vertebra, notable for its prominent spine, connects to the first thoracic vertebra. Thoracic vertebrae serve as attachment points for the true ribs and form part of the chest's posterior. This section of the spine is highly flexible, allowing for bending and twisting. The thoracic vertebrae connect to the lumbar vertebrae, which are robust and large, providing support for the entire body structure while remaining quite flexible. At the spine's upper end, the lumbar vertebrae meet the sacral vertebrae. In adults, the five sacral vertebrae typically fuse into a triangular bone called the sacrum. At the sacrum's lower end, the coccyx, or tailbone, slightly protrudes. It consists of 3 to 5 rudimentary coccygeal vertebrae that have fused together. The vertebral column is also referred to as the spinal column.
