Etymology of Thoracic Terms

With particular thanks to Jack Lyons, MD

Carina - This word for the sharp internal bifurcation of the trachea is the Latin word for the keel of a ship, which it resembles. Our related word for a ship that leans way over so as to show its keel, or a vehicle that sways wildly from side to side, is careen.

Phrenic – The stem of this word, phren, had two separate meanings in ancient Greece. One was the heart or, perhaps because it was so close by, the thoracic diaphragm. Our modern adjective phrenic referring to the diaphragm, as in phrenic nerve, comes from that meaning. The other meaning of phren was the brain or mind. From this second meaning we get such words as phrenology and schizophrenic. Frenzy, at one time spelled phrenzy, also comes from this meaning.

Lingula – This is formed from the Latin word for tongue, lingua, and the diminutive –ula. This lingula is the “little tongue” found on the left lung. Of course you can relate this to words such as linguistics and lingo.

Vagus nerve - Vagus in Latin means wandering or roaming. Cranial Nerve X gets this designation from its wandering nature as it travels through the neck, chest and abdomen supplying various organs and structures therein. Our word vague is directly from this source.

Viscus - the Latin word for an internal organ of one of the body cavities. The plural is viscera. Do not confuse the noun viscus with the adjective viscous meaning sticky or glutinous.

Splanchnic - is from the Greek word splanchna meaning viscera or internal organs. Splanchnic nerves service the viscera.

Mediastinum - This may seem obscure at first glance, but is no more than the prefix media- = middle, and a form of the Latin verb stare = to stand. It is that which stands in the middle (of the thorax).

Ramus - Ramus (plural = rami) is simply the Latin word for a branch. And so for us, all the ramifications of an issue are all its branches or related aspects.

Epicardium - Epi- is a Greek prefix having the meaning on top of or above. Hence epicardium is that which is on top of the cardium, cardium being the Greek word for heart; the corresponding Latin word iscor. You will encounter that root in the medical term cor pulmonaleand in the English word cordial implying coming warmly from the heart.

Auricle - Auris is Latin for ear; -cle is a diminutive, So, an auricle is a little ear. This part of the atrium is also known as the atrial appendage. The technique of examination by listening known as auscultation has a similar, albeit more circuitous, derivation from auris. Incidentally, until Laennec introduced the stethoscope in 1817, “direct auscultation”, carried out by placing one’s ear directly on the chest to listen, was the usual technique.

Atrium - Is the Latin word for the entrance room of a Roman house. In reference to the heart, it is the entrance to the ventricle.

Ventricle - is from the Latinventer(belly or womb) plus the diminutive -cle. So,a ventricle is a little belly. Our English word ventral, therefore, means having to do with the belly side.

Trabecula -In Latin, trabs is the noun for a beam or timber. Trabecula is the diminutive, hence a little beam, which is what those in the heart resemble.

Coronary Artery - Corona means crown in Latin. The coronary arteries rest upon the circumference of the heart like a crown. And you know what happens at a royal coronation - the crown or corona gets put on.

Vena cava - By now you know vena is Latin for vein. Cava means hollow or empty. Hence, the hollow vein. The reason this large vessel was called hollow by the ancients is not surely known. The cav- stem survives in such English words as excavate and cavern.

Azygos - The root Greek word is zygon, meaning a yoke such as unites a team of two oxen and by extension, a pair. The letter a- (preceding -zygos in this case) is known as alpha privative; it expresses negation or that which is not. Unlike most veins, which are bilaterally symmetrical, the azygos is not paired.

Systole - This is formed of two Greek components: Syn- = together, and stellein = to draw or pull. Hence it is a drawing together, a shortening or a contraction - in this case, of the heart.

Diastole - The derivation of the -stole part is the same as in systole (from the Greek verb stellein = to draw or pull). Dia- is a Greek combining form meaning apart. As you may already know, diastole is the portion of the cardiac cycle in which the walls of the ventricles draw apart as the cavities fill. This combining form is also seen in the word diaspora, meaning the drawing apart or scattering of a people.

Thrombosis - Derives from the Greek root thrombos that means a lump or clot. It is usually applied to a blood clot. -Osis usually implies “the condition of having”. So a coronary thrombosis is the condition of having a clot in a coronary artery.

Embolus - This derives from the Greek em- meaning in, and bolos = a throwing. It is something thrown in. In medical parlance, an embolus is a plug of clot (or occasionally other material) that enters the blood and travels down-stream until it jams in a vessel too small to permit its passage. An embolus to a cerebral or coronary artery may produce a cerebral or coronary infarct.

Infarct - The word derives from the Latin verb infarcire = to stuff up. An infarct is an area of tissue death that results from local ischemia due to blockage of circulation to that tissue. In a myocardial infarction it is the arterial blood supply to a portion of heart muscle that gets blocked or stuffed up. Infarcts are most often caused by thrombi or emboli.

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