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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Coccyx. Public domain
Coccyx, anterior view

The word [coccyx] arises from the Greek term [κούκος] (pronounced koúkos)and means "cuckoo". It is the name of the lower segment of the spinal column, and was named by Herophilus of Alexandria (325-255BC) because of a resemblance of this structure to the bill of the cuckoo bird.  Vesalius also used the same analogy. There is another structure of the body named after the beak of a bird, do you know it? If not, click here.

The coccyx (vernacularly known as "tailbone") is usually represented by four rudimentary vertebrae, although the number varies between 3 to 5 vertebrae. There have been reported cases of "human tails" but these do not have a bony structure and are usually related to congenital abnormalities such as spina bifida. 

The coccyx has a well-formed superior component, which usually presents with two cornua (horns) which serve as part of a rudimentary zygapophyseal (facet) joint. The lower coccygeal vertebra is usually a small bony node. 

The coccyx has an anterior sacrococcygeal ligament, which is continued with the anoccygeal raphe, a ligamentous structure that serves as a posterior attachment for muscular components of the pelvic diaphragm, and helps anchor the anal canal. The coccygeus muscle, the posterior component of the pelvic diaphragm and part of the sacrospinous ligament also attach to the anterolateral aspect of the coccyx.

Coccygeal pain is referred to as coccydynia.

1. "The Origin of Medical Terms" Skinner, HA 1970 Hafner Publishing Co.
2. "Medical Meanings - A Glossary of Word Origins" Haubrich, WD. ACP Philadelphia
3. "Dorlands's Illustrated Medical Dictionary" 26th Ed. W.B. Saunders 1994
5 "Tratado de Anatomia Humana" Testut et Latarjet 8 Ed. 1931 Salvat Editores, Spain
6. "Anatomy of the Human Body" Henry Gray 1918. Philadelphia: Lea & Febiger
Image modified by CAA, Inc. Original image courtesy of

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