What do we call the last three or four vertebrae of the spine, also known as the tailbone?

The term for the last three or four vertebrae of the spine, commonly referred to as the tailbone, is coccyx. The coccyx is a small, triangular bone situated at the very end of the vertebral column. It is formed by the fusion of several vertebrae and serves as an important attachment site for various muscles, tendons, and ligaments.

The coccyx plays a role in supporting the weight of the body when sitting and helps provide balance and stability. It is distinct from other parts of the spine such as the sacrum, which consists of five fused vertebrae located just above the coccyx and is part of the pelvis. The thoracic vertebrae and lumbar vertebrae refer to sections of the spine located higher up, with thoracic being associated with the rib cage and lumbar consisting of larger vertebrae in the lower back region. Understanding the nomenclature and function of these different sections is essential for a deeper comprehension of human anatomy.