The human ribcage consists of several pairs of ribs that are categorized primarily into true ribs, false ribs, and floating ribs. The main difference between true ribs and false ribs lies in their attachment to the sternum and the other ribs.
True Ribs: True ribs refer to the first seven pairs of ribs in the ribcage, which are directly attached to the sternum via individual costal cartilages. This direct connection allows for more stability and structure in the chest cavity, which can help protect vital organs like the heart and lungs.
False Ribs: False ribs, on the other hand, consist of the next five pairs of ribs. These ribs do not attach directly to the sternum. Instead, pairs 8 to 10 are connected to the costal cartilage of the seventh rib, which makes their connection to the sternum indirect. This structural difference means that false ribs do not provide as much stability as true ribs, although they still contribute to the overall protection of the thoracic cavity.
Additionally, the last two pairs of false ribs (ribs 11 and 12) are often referred to as floating ribs because they do not connect to either the sternum or other ribs. They are only attached to the vertebrae at the back and thus are free at the front.
In summary, the distinction between true ribs and false ribs is primarily based on their anatomical connections to the sternum—true ribs attach directly, while false ribs attach indirectly or not at all.