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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Coronary arteries

The term [coronary] comes from the Latin root [corona] meaning "crown", therefore [coronary] is used to denote a structure that surrounds another as a crown or a garland. In the heart, the coronary arteries and their branches form a crown that surrounds the heart at the level of the atrioventricular sulcus. There are two coronary arteries, the right coronary artery (RCA), and the left coronary artery (*). Both these coronary arteries are the only branches that arise from the ascending aorta.

The right coronary artery passes from the anterior to the posterior surface of the heart, ending in a terminal branch, the posterior descending artery, or PDA. The left coronary artery, sometimes called the "left main", gives origin to two branches: the circumflex artery (CFX) and the left anterior descending artery (LAD). Each one of these arteries gives origin to several named branches. 

Coronary Arteries
There can be interesting anatomical variations in the coronary arteries of the heart. Heart and coronary artery anatomy is one of the topics developed and delivered by CAA, Inc.

Image property of: CAA.Inc.Artist: Victoria G. Ratcliffe

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The Latin word [ventriculus] means "little sac" or "little belly" and arises from the Latin term [venter] meaning "belly" or "abdomen". Originally the term [ventricle] was used to denote the stomach. This use of the word has changed and now the term [ventricle] denotes a "sac" or "cavity", as in the "ventricles of the brain". The term [ventricular] means "pertaining or related to a ventricle".

In the case of the heart, the ventricles represent the two inferior chambers of the heart. (see image, items "C=right ventricle" and "D=left ventricle"). The anatomy of the right and left ventricles is quite different. The left ventricle has a thicker lateral muscular wall, almost three times thicker than the lateral wall of the right ventricle.

Image property of: CAA.Inc.Photographer: D.M. Klein

Heart model - LAO cranial view
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The term [perineum] has two definitions:

1. It is the area of the trunk inferior to the pelvic diaphragm. As such, the perineum contains the ischioanal fossa, the urogenital diaphragm, and the superficial genitalia.

2. It is the area of the body between the upper thighs containing the external openings of urethra, vagina, and anus. This area is delimited (see image) by the symphysis pubis, ischial tuberosities, and coccyx.

The perineum, as described in the second definition, is formed by two large triangular regions. The anterior region (in purple) is called the urogenital triangle, and the posterior region (in yellow) is called the anal triangle. 

Image property of: CAA.Inc.. Artist: D.M. Klein.
Word suggested and edited by: Dr. Sanford S. Osher , MTD Contributor

Perineum, inferior view
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Pelvic diaphragm

The pelvic diaphragm is one of the four diaphragms in the human body (do you know the other three?) and it represents the lower boundary of the abdominopelvic cavity. This thin and  transversely oriented structure is formed from anterior to posterior by the puboccygeus, the iliococcygeus, and the coccygeus muscles.

The first two anterior muscles overlap, the pubococcygeus muscle being superior to the iliococcygeus muscle. Both of them attach laterally to a thickening of the obturator internus fascia that covers the obturator internus muscle. This thickening is known as the arcus tendineus levator ani (ATLA in the image). Because of the relation of the medial fibers of the puboccygeus muscle to the anal canal (puborectalis muscle), and what happens when these muscles contract, these two anterior muscles are known by one common name, the "levator ani" muscle. Click on the picture for a larger image.

Pelvic diaphragm, superior view
The posterior component of the pelvic diaphragm is the coccygeus muscle, which is found lying on the internal aspect of the sacrospinous ligament.
Image property of: CAA.Inc.Artist: D.M. Klein
Word suggested and edited by: Dr. Sanford S. Osher, MTD Contributor
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The root word [-gyne-] is Greek, from [gynaik] meaning "woman" or "female". The suffix [-ology] is also Greek,  derived from [logos] meaning "study of". [Gynecology] is then "study of a woman or a female". The term refers to the medical specialty that studies and treats the female reproductive system. A separate specialty, obstetrics, deals with the care of the pregnant patient and delivery of the fetus.

Originally, both specialties were the domain of midwives. It was not until the 1600's that male physicians were allowed to treat gynecological problems and attend  births. As the image shows, man-widwifes in Europe were allowed access to the patient only with the use of a "modesty blanket". This is plate XV from the 1681 book "Korte en Bondige Van Der Voortteeling en Kinderbaren" by Samuel Janson.

A man-midwife and a 'modesty blanket' c.1681
As an interesting side note in history, the first male physician to work as a man-midwife was Dr. Wertt from Hamburg. Dr Wertt decided to disguise himself as a woman to attend patients. When he was discovered, the punishment was "swift and salutary": He was burned at the stake.
"The Story of Surgery" by H. Graham, 1939
Word suggested and edited by: Dr. Sanford S. Osher , MTD Contributor
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From the Greek word [stoma] meaning "mouth or opening", and the suffix [-y] meaning "process or condition". The suffix [-(o)stomy] refers to the "process of creating an opening". This process can be physiological, without intervention, as in the creation of a spontaneous fistula, or it can be a surgical procedure.

As a working explanation of [-ostomy] in surgery, we like to use the term "drainage". Therefore, an [ileostomy] would be the procedure by means of which a drainage opening is creating an anastomosis between the ileum and the abdominal wall.

The accompanying image shows an early 1900's procedure to create a gastrostomy (Wietzel's gastrostomy). The root term [gastr-] means "stomach".

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