Final answer:
The costal groove is organized on the inferior margin of each rib, providing passage for blood vessels and a nerve. Ribs can attach to the sternum directly or indirectly, depending on their type. Floating ribs do not attach to the sternum or another rib.
Step-by-step explanation:
The costal groove is organized on the inferior margin of each rib and provides passage for blood vessels and a nerve.
Posteriorly, the head of each rib articulates with the costal facets on the thoracic vertebrae, while the rib tubercle articulates with the facet on the vertebral transverse process.
True ribs (1-7) attach directly to the sternum via their costal cartilage, while false ribs (8-12) attach indirectly or not at all. The floating ribs (11-12) do not attach to the sternum or another rib.