What bones comprise the rib cage?

• A. True ribs attach directly to the sternum; false ribs attach indirectly via cartilage; floating ribs do not attach anteriorly; sternum and thoracic vertebrae.
• B. True ribs attach indirectly via cartilage; false ribs attach directly to sternum; floating ribs attach anteriorly.
• C. True ribs (1–7) attach directly to sternum; false ribs (8–10) attach indirectly via cartilage; floating ribs (11–12) do not attach anteriorly.
• D. All ribs attach directly to the sternum.

Answer: (C)

The rib cage is described by how the ribs connect to the sternum. The first seven pairs, called true ribs, attach directly to the sternum through their own costal cartilage. The next three pairs, known as false ribs, do not attach directly to the sternum but connect to the cartilage of the rib above, forming indirect attachment to the sternum. The last two pairs are floating ribs; they do not attach to the sternum at all and end anteriorly in the muscle tissue of the chest wall. Together with the sternum and the thoracic vertebrae, these ribs form the complete rib cage.