The combining form stern(o) relates to which anatomical structure?

• A. Rib
• B. Heart
• C. Lungs
• D. Sternum

Answer: (D)

Stems in medical terms map directly to the structures they name. The combining form stern(o) points to the sternum, the breastbone at the center of the chest. This bone forms the anterior part of the rib cage and connects to the ribs. You’ll see stern(o) in terms like sternocostal or sternocleidomastoid, where the reference is to the sternum or its relation to other structures. The rib has its own root, cost/o; the heart has cardi/o; the lungs have pulmon/o or pneumon/o. So stern(o) specifically denotes the sternum.