The vertebral column is an incredible structure combining dozens of bones, hundreds of articulations and a myriad of muscles. It houses the inferior portion of the central nervous system (CNS), the spinal cord, and it provides a base for the upper and lower extremities. The vertebral column supports the head and rib cage. All of these while accommodating the mechanism for providing erect posture.

The vertebral column is composed of five distinct sets of vertebrae. Although connected, each has a slightly different structure and function:

• Seven cervical - support the head and provide passage of important arteries to the brain.
• Twelve thoracic - articulate with and help support the ribs and rib cage.
• Five lumbar - support most of the trunk, head and upper extremities, providing a strong attachment base for the muscles that move the trunk and upper limbs.
• Five fused sacral - greatly modified to articulate with the hip bones and transfer weight from the upper body to the lower extremities. They also provide a firm foundation for many powerful trunk muscles.
• Three to five coccygeals - vestigial in humans.