The sternum is the flat bone down the middle of your chest, at the front. Put your hand between your two collarbones and slide it downwards — that hard, flat strip is it.

The sternum is the flat bone down the middle of your chest, at the front是位在你胸口正中央前方的一塊扁平骨頭。Put your hand between your two collarbones and slide it downwards把手放在兩邊鎖骨中間，往下滑 — that hard, flat strip is it摸到那條又硬又扁的東西就是它。

Its job is to hold the front ends of your ribs together, so your ribs form a cage around your heart and lungs instead of hanging loose. In plain conversation, English speakers say breastbone; sternum is the medical word, what a doctor, nurse or anatomy book uses.

Its job is to hold the front ends of your ribs together它的作用是把肋骨的前端固定在一起 so your ribs form a cage around your heart and lungs instead of hanging loose這樣肋骨才能在心臟和肺周圍形成一個籠子，而不是鬆散地垂著。In plain conversation在日常對話裡 English speakers say breastbone英語人士會說breastbone sternum is the medical word, what a doctor, nurse or anatomy book usessternum是醫學用字，是醫生、護理師或解剖學課本會用的字。

Both are perfectly correct — the choice tells you the setting, not the meaning. You will meet sternum most often in three places: first aid classes (CPR pushes on the lower half of it), sports and gym talk (chest exercises, 'bring the bar to your sternum'), and hospital talk about heart surgery, where the surgeon must cut through it to reach the heart.

Both are perfectly correct兩種說法都完全正確 — the choice tells you the setting, not the meaning用哪一個只是反映場合，不是意思不同。You will meet sternum most often in three places你最常在三種場合遇到sternum這個字 first aid classes (CPR pushes on the lower half of it)急救課（CPR按壓的位置就是它的下半部） sports and gym talk (chest exercises, 'bring the bar to your sternum')運動健身的講法（胸部訓練，像「把槓鈴帶到sternum」） and hospital talk about heart surgery, where the surgeon must cut through it to reach the heart還有醫院講心臟手術時，因為外科醫生必須切開它才能到達心臟。

The plural is sternums in ordinary use, or sterna if you want the Latin form, which biologists prefer. There is also an adjective, sternal, as in 'sternal pain'.

The plural is sternums in ordinary use一般用法的複數是sternums or sterna if you want the Latin form, which biologists prefer如果要用拉丁文形式、也就是生物學家偏好的說法，就是sterna。There is also an adjective, sternal, as in 'sternal pain'還有一個形容詞sternal，像'sternal pain'（胸骨痛）這樣用。

Small anatomy bonus: the little pointed tip at the bottom of it has its own name, the xiphoid process, and first-aid teachers warn you not to press on it.

Small anatomy bonus解剖學小知識 the little pointed tip at the bottom of it has its own name它下端那個小小的尖端有自己的名字 the xiphoid process叫做劍突 and first-aid teachers warn you not to press on it急救老師會提醒你不要壓到那裡。