Final answer:
The articulations of ribs 2-9 involve their head attaching to the thoracic vertebrae's costal facets and the tubercle connecting to the transverse process facet, with anterior attachments to the sternum via costal cartilage, except for ribs 8-10.
Step-by-step explanation:
The articulations of ribs 2-9 involve specific structural interactions with the thoracic vertebrae. Each rib articulates posteriorly at two main points: the head of the rib attaches to the costal facets on the bodies of the thoracic vertebrae, and the tubercle of the rib connects to the facet on the thoracic vertebra's transverse process.
Anteriorly, these ribs, excluding 8-10, attach to the sternum via their costal cartilage. Ribs 8-10, known as vertebrochondral ribs, attach indirectly to the sternum by connecting to the costal cartilage of the rib above. The angle of the ribs represents the point with the greatest curvature and forms the most posterior extent of the thoracic cage.