How many small bones make up the backbone?

The backbone, or vertebral column, is comprised of 26 individual vertebrae in adults. These vertebrae are divided into several regions: seven cervical vertebrae in the neck, twelve thoracic vertebrae in the upper back, and five lumbar vertebrae in the lower back. Additionally, the sacrum and coccyx are formed from fused vertebrae, but they are not counted as individual bones in terms of the backbone’s structure.

Understanding the arrangement and count of these vertebrae is crucial in fields such as anatomy and healthcare. Since the sacrum consists of five fused sacral vertebrae and the coccyx comprises four fused coccygeal vertebrae, these categories contribute to the overall spinal structure but are distinct from the count of individual movable vertebrae. Therefore, considering only the small, individual bones that contribute to the flexible backbone, there are 24 movable vertebrae. However, when including the sacrum and coccyx, the total number of bones in the spinal column during adulthood is typically summarized as 26, accounting for both the individual vertebrae and the fused segments not counted as separate small bones.