The T9 vertebra is one of the lowest positioned of the twelve (12) thoracic vertebrae, and thus one of the largest. While the T2-T9 vertebrae are often linked descriptively, the T9 vertebra has certain particularities. Instead of two costal demi-facets (superior and inferior) on the exterior of the centrum, it typically has a single superior costal demi-facet above, which together with facets on the transverse bodies provides articular spaces for the tubercular heads of the connecting ribs. Otherwise, the T9 greatly resembles the T2-T8 vertebrae in having a centrum (ventral body) in the shape of a heart, with flat articular surfaces above and below, creating a joint with the T8 vertebra above and the T10 below, with cartilaginous intervertebral discs between to cushion the joints and provide support to the spine. The T9 has a smaller (and circular) vertebral foramen than the vertebrae above it. Its laminae are large and overlap with the T10 vertebra.