Answer
There are twelve pairs of ribs in both males and females. Ribs 1 through 7 are called true ribs. Each true rib has its own costal cartilage connecting it to the sternum. Ribs 8 through 12 are called false ribs because they do not have their own independent connections to the sternum . The third group of ribs is the floating ribs-- numbers 11 and 12. These are so designated because although they articulate with the bodies of vertebrae T11 and T12, they are not attached to the transverse processes of these vertebrae. At there distal ends, ribs 11 and 12 taper to a point and are covered by a small tip of cartilage. But they are not connected to the sternum or to any of the other superior costal cartilages.
Work Step by Step
In most Americans only ribs 11 and 12 are floating, but in some ethnic groups rib 10 is also a floating rib.
