sternum

American  

[stur-nuhm] / ˈstɜr nəm /

noun

plural

sterna, sternums

1. Anatomy, Zoology. a bone or series of bones extending along the middle line of the ventral portion of the body of most vertebrates, consisting in humans of a flat, narrow bone connected with the clavicles and the true ribs; breastbone.

2. the ventral surface of a body segment of an arthropod.

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sternum British  

/ ˈstɜːnəm /

noun

1. Nontechnical name: breastbone.  (in man) a long flat vertical bone, situated in front of the thorax, to which are attached the collarbone and the first seven pairs of ribs

2. the corresponding part in many other vertebrates

3. a cuticular plate covering the ventral surface of a body segment of an arthropod Compare tergum

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sternum Scientific  

/ stûr′nəm /

1. A long, flat bone located in the center of the chest, serving as a support for the collarbone and ribs.

2. Also called breastbone

3. See more at skeleton

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Other Word Forms

• sternal
  adjective

Etymology

Origin of sternum

1660–70; < New Latin < Greek stérnon chest, breastbone

Explanation

Your sternum is your breastbone, the flat plate at the top of your rib cage. Mammals and birds — and even arachnids, or spiders — have a sternum. If you study human anatomy, you'll learn that the sternum is a long, flat, T-shaped bone made of fused segments. The rib cage attaches the sternum to the spine, or vertebrae. The word itself comes from the Greek sternon, "chest, breast, or breastbone," from a root that means "flat surface."

Example Sentences

One fossil revealed a segmented cartilaginous sternum, along with sternal ribs, intermediate ribs, and connections linking the ribcage to the shoulder girdle.

From Science Daily • Apr. 23, 2026

Heart surgery is extremely traumatic, physically and emotionally, and requires at least three months of recovery, and many months more for your husband’s sternum to fully heal.

From MarketWatch • Jan. 22, 2026

Sutures, as in the skull, don’t move in adults, and cartilaginous joints, such as those that connect the ribs to the sternum, tend to have very limited mobility.

From Science Magazine • Apr. 25, 2024

Quarterback Collin Schlee, who suffered an apparent sternum injury against Oregon State, did not practice Monday and was “unavailable,” according to Kelly.

From Los Angeles Times • Oct. 16, 2023

I swallow a breath and try to hold it behind my sternum as I gingerly tilt and try to put weight on the leg, but I can’t.

From "The Sea in Winter" by Christine Day