Final answer:
The thoracic vertebrae are larger than the cervical vertebrae and are distinguished by the fact that they are the only vertebrae to articulate with ribs.
Step-by-step explanation:
Each thoracic vertebra possesses facets on the transverse processes and the body for rib articulation. This unique feature allows the thoracic vertebrae to form joints with the ribs, contributing to the structure of the ribcage.
The articulation of ribs with the thoracic vertebrae provides stability and support to the spine while also accommodating the thoracic cavity, protecting vital organs such as the heart and lungs.
This specialization reflects the structural adaptation of the thoracic vertebrae to their role in forming the posterior part of the thoracic cage.