Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community. We post anatomical, medical or surgical terms, their meaning and usage, as well as biographical notes on anatomists, surgeons, and researchers through the ages. Be warned that some of the images used depict human anatomical specimens.

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A Moment in History

Jean-Louis Petit

Jean Louis Petit
(1674 – 1750)

French surgeon and anatomist, Jean Louis Petit was born in Paris in on March 13, 1674.  His family rented an apartment at his house to Alexis Littre (1658 – 1726), a French anatomist. Petit became an apprentice of Littre at seven years of age, helping him in the dissections for his lectures and at an early age became the assistant in charge of the anatomic amphitheater.

Because of Petit’s dedication to anatomy and medicine, in 1690 at the age of sixteen, became a disciple of a famous Paris surgeon, Castel.

In 1692, Petit entered the French army and performed surgery in two military campaigns. By 1693 he started delivering lectures and was accepted as a great surgeon, being invited to the most difficult operations.  In 1700 he was appointed Chief Surgeon of the Military School in Paris and in the same year he received the degree of Master of Surgery from the Faculty of Paris.

In 1715 he was made a member of the Royal Academy of Sciences and an honorary member of the Royal Society of London. He was appointed by the King as the first Director General of the Royal Academy of Surgery when it was founded in 1731.

Petit’s written works are of historical importance.  “Traite des Maladies des Os” ( A Treatise on Bone Diseases);  “Traite des Maladies Chirurgicales et des Operation” (A Treatise on Surgical Diseases and their Operations” This last book was published posthumously in 1774. He also published a monograph on hemorrhage, another on lachrymal fistula, and others.

He was one of the first to perform choIecystotomy and mastoidotomy. His original tourniquet design for amputations saved many in the battlefield and the design of the same surgical instrument today has not changed much since its invention by him.

His name is remembered in the lumbar triangle, also called the "triangle of Petit", and the abdominal hernia that can ensue through that area of weakness, the lumbar hernia or "Petit's hernia".

1. “Jean Louis Petit – A Sketch of his Life, Character, and Writings” Hayne, AP San Fran Western Lancet 1875 4: 446-454
2. “Oeuvres compl?tes de Jean-Louis Petit” 1837 Imprimerie de F. Chapoulaud
3. Extraits de l'eloge de Jean-Louis Petit Ius dans Ia seance publique de I' Academie royale de chirurgie du 26 mai 1750” Louis A. Chirurgie 2001: 126 : 475- 81

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The medical term embolus arises from the Greek [έμβολο] (pronounced émvolo) meaning "a plug", or "a plunger". This Greek term was later adopted in Latin [embolus] and is used in this unchanged form today. The plural for embolus is [emboli].

In medicine, the term embolus usually refers to a free blood clot that travels down the bloodstream. When in the veins, emboli will travel easily to and through the heart. This is because veins increase in diameter towards the heart. The opposite happens in arteries. Free blood clots (emboli) that passed through the heart with no problem now enter the pulmonary arteries whose branches get smaller and smaller until the emboli plug the arterioles, and now the patient has a pulmonary embolism.

When thrombi are generated in the heart, they are usually generated in the left atrial appendage in cases of arrhythmia or atrial fibrillation.  If these thrombi embolize, that is, they become free, these now emboli will continue downstream in the arteries and progressively smaller arterioles until they are bigger that the vessel and plug it, cutting off blood supply. This condition can cause an infarction, also known as a stroke. 

The term embolus can also refer to liquids. fat, or gases that enter the blood stream and are not diluted. 

The first use of this term in modern medicine was by Virchow in 1846 in his paper "On the Occlusion of the Pulmonary Arteries"

The root term for this word is [-embol-]. Examples of its use are:

Embolism:  The suffix [-ism] means "behavior" or "pathology".
• Thromboembolism: A combination of root terms; the root term  [-thromb-] means "fixed clot" and [-embol] means "a free clot". A condition or presence of both trombi and emboli.

1. "The Origin of Medical Terms" Skinner, HA 1970 Hafner Publishing Co.
2. "Medical Meanings - A Glossary of Word Origins" Haubrich, WD. ACP Philadelphia