sternum

American  

[stur-nuhm] / ˈstɜr nəm /

noun

sterna, plural sternums plural

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

Derived Forms

• sternal
  adjective

Inflected Forms

Nouns

• sterna
  plural
• sternums
  plural

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

See Examples For:

sternum sterna sternums

I kind of went in head first and it felt like I broke my sternum.

From The Wall Street Journal ● Jun. 22, 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

If so, was it wedged against his sternum?

From BBC ● May 27, 2025

But in sharp contrast, the sternum from the same mice displayed "profound reductions" in these cell types as well as loss of neutrophil production sites.

From Science Daily ● Mar. 20, 2024

But I still felt the burn of jealousy behind my sternum.

From "Darius the Great Is Not Okay" by Adib Khorram

They may be distinguished from the Malacodermata by the presence of only five or six abdominal sterna, while six malpighian tubes are present in some of the families.

From Encyclopaedia Britannica, 11th Edition, Volume 6, Slice 6 "Cockaigne" to "Columbus, Christopher" by Various

Pectoral Girdle.—The pectoral girdles are fully arciferal and bear small, cartilaginous omosterna and moderately large cartilaginous sterna.

From A Synopsis of Neotropical Hylid Frogs, Genus Osteocephalus by Duellman, William E.

In many genera of the Pentatomidae, bristle-bearing tubercles on the legs are scraped across a set of fine striations on the abdominal sterna.

From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 3 "Helmont, Jean" to "Hernosand" by Various

Each leg-bearing somite contains a distinct tergum and sternum, the number of sterna never exceeding that of the terga.

From Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 6 "Celtes, Konrad" to "Ceramics" by Various

The first and second abdominal sterna are often suppressed or reduced, on account of the strong development of the hind-legs.

From Encyclopaedia Britannica, 11th Edition, Volume 13, Slice 4 "Hero" to "Hindu Chronology" by Various

Some animals are born with kinked tails and deformed sternums.

From Science Magazine ● Jan. 13, 2022

Dr. Prieto called in a colleague, Katya Valladares, who investigated the skeletons and identified cut marks on many of the children’s sternums.

From New York Times ● Mar. 6, 2019

A line of pale models, their sternums outlined under parchment skin, wound its way around the bare concrete benches, while overhead hung rows of curved and flat translucent panels made from fiberglass and corrugated polycarbonate.

From The Wall Street Journal ● Nov. 5, 2015

They'd gone from cruising to crisis in a heartbeat – and their hearts were beating harder than ever, smashing through their sternums.

From The Guardian ● May 10, 2010

Birds' sternums are a great deal more than surfaces of origin for the pectoral muscles—e.g. movable lid of respiratory bellows.

From Life and Letters of Thomas Henry Huxley — Volume 3 by Huxley, Leonard