Which vertebra is comprised of five fused vertebrae?

The sacral vertebrae are composed of five fused vertebrae that form the sacrum, a triangular bone located at the base of the spine. This structure is significant because the fusion of these vertebrae provides stability and support for the pelvis, making it an essential part of the skeletal system.

In contrast, the cervical vertebrae consist of seven individual vertebrae that make up the neck region, allowing for a wide range of motion. Thoracic vertebrae consist of twelve individual vertebrae in the upper back that articulate with the ribs. The lumbar vertebrae contain five separate vertebrae in the lower back, which are larger and designed to support more weight and provide flexibility.

Understanding the anatomy and fusion of the sacral vertebrae is crucial for recognizing how they contribute to the overall stability and function of the spine and pelvis.