What distinguishes false ribs from true ribs?

The distinction between false ribs and true ribs primarily lies in their attachment to the sternum. True ribs are directly connected to the sternum via costal cartilage, allowing them to articulate firmly with the sternum itself. In contrast, false ribs do not have this direct connection. Instead, they either connect indirectly through the cartilage of the rib above or do not connect to the sternum at all.

The correct answer highlights that false ribs, specifically those designated as the 8th to 12th pairs in humans, either share cartilage connections with the ribs above them or, in the case of floating ribs (the last two pairs), do not connect to the sternum at all. This anatomical difference is crucial for understanding the structure and function of the ribcage. Floating ribs are considered a subtype of false ribs because they lack any attachment to the sternum.

The other options do not encapsulate this fundamental aspect of rib differentiation, making the correct understanding crucial for clear knowledge of human anatomy and its implications in various medical contexts.