Final answer:
The body of the thoracic vertebrae is somewhat heart-shaped and features two costal facets (articulating surfaces) on each side, providing points of articulation for the heads of the ribs.
Step-by-step explanation:
With two costal facets (articulating surfaces) on each side, the thoracic vertebrae's body has a somewhat heart-shaped shape and serves as points of articulation for the rib heads. This special structure enables the ribs to be attached and supported, aiding in the creation of the thoracic cage and safeguarding important organs inside the chest cavity.
The articulation of the ribs and thoracic vertebrae is an important component of the vertebral column's flexibility and stability, allowing for a variety of motions and preserving the ribcage's overall integrity.