[Plate 180, Ribs and Sternocostal Joints]All ribs contain bone marrow.
Ribs 1 through 7 are vertebrocostal because they attach to the sternum via a costal cartilage.
Ribs 8 through 10 are vertebrochondral because their cartilages are joined to the cartilage of the rib above and via that connection to the
sternum.
Ribs 11 and 12 are free or floating ribs, which do not connect even indirectly with the sternum but which have a costal cartilage on their tips.
First rib is broad and sharply curved and has a tubercle of the attachment of scalene muscles.