Which vertebrae possess special facets for articulation with the ribs?

The thoracic vertebrae are the only vertebrae that possess special facets for articulation with the ribs. Each thoracic vertebra has costal facets that interact with the heads of the ribs, helping to form the thoracic cage which is crucial for protecting vital organs such as the heart and lungs.

These facets allow for a connection point where the ribs can attach, providing stability and support during breathing movements. The unique structure of the thoracic vertebrae, including the presence of these facets, makes them distinct from cervical, lumbar, and sacral vertebrae. Cervical vertebrae do not have these facets, as they primarily support the neck and allow for a wide range of head motion. Lumbar vertebrae are designed to bear weight and do not feature rib articulation. The sacral vertebrae are fused and form part of the pelvis, which also does not involve rib articulation. Therefore, the thoracic vertebrae's specialized facets for rib articulation is a defining characteristic of their structure and function.