Rib: There are 12 pairs of ribs in the body. The first 7 pairs of ribs articulate with the sternum by cartilaginous attachments. These are called the true ribs. The last 5 pairs if ribs are called false ribs because they do not join the sternum directly. Instead, the first 3 (the 8th, 9th, and 10th) have cartilage which converges before the sternum is reached. The last two are floating ribs which end in the midchest; they are not attached to the sternum at all. All the ribs are attached to the vertebral column dorsally and form a cage-like structure enclosing and protecting the heart, lungs, and other thoracic structures.