Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community, medical students, and the medical industry. We will post a workweek daily medical or surgical term, its 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

Giovanni Batista Morgagni
Original image courtesy of National Institutes of Health

Giovanni Battista Morgagni

(1682 - 1771)

Italian anatomist, physician, and pathologist, Morgagni was born in the city of Forli. He started his medical studies at the University of Bologna, graduating in 1701 with a degree in Medicine and Philosophy. In 1712 he became a professor of anatomy at the University of Padua, Italy, 175 years after Andreas Vesalius. Morgagni was offered and accepted the Chair of Anatomy in 1715 at the University of Padua. Although Morgagni held a position at the anatomy department of the University of Padua, his name is associated mostly with his pathological studies.

Morgagni was interested in the works of Theophile Boneti (1620 - 1689), who started analyzing the correlation between post-mortem anatomical findings and diseases. He tried to establish a relation between the disease and the cause of death. In 1761 Morgagni published his most influential work "De Sedibus et Causis Morburum Per Anatomen Indagatis"  (On the Sites and Causes of Diseases, Investigated by Dissection). His work was essential for pathological anatomy to be recognized as a science in itself.

Morgagni was elected to become a member of several Academies of Science and Surgery: The Royal Society of London, The Academy of Science in Paris, The Berlin Academy of Science, and the Imperial Academy of Saint Petersburg in Russia. He is remembered today by several eponyms in anatomy and pathology:

• Morgagni's caruncle or lobe, referring to the miidle lobe of the prostate
• Morgagni's columns: the anal (or anorectal) colums
• Morgagni's concha, referring to the superior nasal concha
• Morgagni's foramina: two hiatuses in the respiratory diaphragm allowing for passage of the superior epigastric vessels
 Morgagni's hernia: an hiatal hernia through Morgagni's foramen, in the respiratory diaphragm
• Morgagni's ventricle: an internal pouch or dilation between the true and false vocal cords in the larynx
• Morgagni's nodules: the nodules at the point of coaptation of the leaflets (cusps) of the pulmonary valve. Erroneously called the "nodules of Arantius", which are only found in the aortic valve

1. "A Note From History:The First Printed Case Reports of Cancer" Hadju, S.I. Cancer 2010;116:2493–8
2. "Giovanni Battista Morgagni" Klotz, O. Can Med Assoc J 1932 27:3 298-303
3. "Morgagni (1682 -1771)" JAMA 1964 187:12 948-950

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The lost influence of Andreas Vesalius on eponymic anatomy

Andreas Vesalius Bruxellensis (1515-1564) is considered to be the father of modern anatomy, remembered because an illustrious life and by his book “De Humani Corporis Fabrica, Libri Septem” published first in 1543. Scores of books, translations, articles, and analyzes of his work have been published in the over 500 years since his birth.

With such an incredible pedigree we would expect his name to be attached to more than a few anatomical structures, many of which were first described in his opus magnus, the “Fabrica”, I wonder why this is not so. It is true that modern anatomy is trying to move from eponyms to more descriptive anatomical terms. Still, there are many that will not go away, as is the famous ligament of Treitz, or the sphincter or Oddi.

Today there is only one recorded eponym for Andreas Vesalius, the os vesalianum, a rare accessory bone in the foot located proximally to the base of the fifth metatarsal. It is usually asymptomatic, but in rare cases it can cause pain. It is formed by the failed fusion of the secondary ossification center of the fifth metatarsal.

Reviewing history, I was able to find other references to Andreas Vesalius eponyms or potential eponyms, now in disuse or misnamed:

Andreas Vesalius Bruxellensis
Suspensory ligaments of the mammary gland. Although first described by Vesalius in the Fabrica, these structures are named after Sir Astley Paston Cooper (1768 -1841), almost 300 years after being described by the great anatomist, who called them a “fleshy membrane” that stretched between the pectoral fascia and the skin.

- The vermiform appendix. Although called by many just “the appendix”, this structure is mentioned, but not named, by Jacobo Berengario da Carpi in 1524. It was Andreas Vesalius who first described it as an appendix, suggested it looked like a worm (Lat: vermis) calling it the “vermiform appendix”.

- The ligamentum suspensorium Vesalii or crural arch. First described by Giovanni Baptista Morgagni (1682-1771), it was named in honor of Vesalius by Dr. Laurentii (Lorenz) Heisters in his “Compendium Anatomicum” published in 1756. Other authors point to Gabrielle Fallopius as the first to describe this structure in 1561, although he did publish later than Vesalius (1543). Although named after Vesalius, it was later named after Francois Poupart who described it in 1695. You probably know this structure as the inguinal ligament.

-The ligamentum teres femoris. The round ligament of the femur was also first described by Vesalius in 1543.

NOTE: If you have other structures that have been named after Vesalius, please let me know by clicking here.

1. “A Rare Cause of Foot Pain with Golf Swing. Symptomatic Os Vesalianum Pedis—A Case Report” Petrera, M et al. Sports Health. 2013 Jul; 5(4): 357–359.
2. “Andreas Vesalius’ 500th Anniversary: First Description of the Mammary Suspensory Ligaments” Brinkman RJ, Hage, JJ. World J Surg (2016) 40:2144–2148
3. “Compendium Anatomicum” Heisters, L. 1756 (German)
4. “Anatomy: An Encyclopedic Reference to the Language of Anatomy and Neuroanatomy. It Provides the Fascinating Origin of Terms and Biographies of Anatomists/Physicians Who Originated Them” Bergman, RA, Afifi, AK 2016


UPDATED: From the Greek [ep(i)] meaning "outer, above, or upon", and the Greek suffix [o-nym] meaning "name". The word [eponym] refers to a person's name becoming attached to an anatomical location or surgical procedure. For centuries it has been the custom to honor or remember someone by attaching their name to a structure, location, procedure, or maneuver.

This has changed as anatomists tend now to give locations and structures descriptive terms. An example of this would be the "Ampulla of Vater" named after the German anatomist Abraham Vater (1684-1751) described today in anatomical texts as the "hepatopancreatic ampulla". The controversy on using eponyms or not goes on...

There are many eponymical terms in the medical arena; following are some of them, click on the links for additional information:

Hesselbach’s triangle: Named after Franz Kaspar Hesselbach (1759-1816) (see yellow insert in superior image)
Spigelian line (linea semilunaris): Site for an Spigelian hernia, named after Adrian Van Der Spigelius (1578-1625) (see blue arrow in inferior image)
Fallopian tube: Named after Gabrielle Fallopius (1523-1563)
Cooper's pectineal ligament. Named after Sir Astley Paston Cooper (1768-1841)
Hartmann's procedure: A two-stage colon resection and anastomosis. Named after Prof. Henri Hartmann (1860-1952), a French surgeon.
Heimlich's maneuver:  Named after Dr. Henry J. Heimlich (1920 - )
Ligament of Treitz: Named after Václav Treitz (1819 - 1872), a Czech pathologist.

If you want to see a listing of the eponyms in this website, click here.

Here is an article on "The lost influence of Andreas Vesalius on eponymic anatomy".

Here is an interesting article on eponyms by Ilana Yurkiewicz published on 11/15/2012 in Scientific American: "Modern medical terms are still named after Nazi doctors. Can we change it?". It is interesting and thougthful reading.

PERSONAL NOTE: Many anatomists today are actively trying to eliminate eponyms from anatomical, medical, and surgical books. For me, this eliminates the interest of learning about the people who either first described these structures or procedures, which is one of the objectives of this website. I wonder (and this is a tongue-in-cheek comment) if the reason for this desire to eliminate eponyms is because there are so many attached to anatomical structures that there is no place for their own names! When history has forgotten about the original eponyms maybe we will see new ones with the names of modern anatomists! I do not worry, my name is attached to the "Ligaments of Miranda". Dr. Miranda

Superior image property of: CAA.Inc.. Artist: M. Zuptich.
Inferior image property of:CAA.Inc.. Artist:D.M. Klein

Ascending aorta

UPDATED: The ascending aorta is the first and most proximal portion of the aorta. About 5 cm. in length and 3 cm. in diameter at its origin, its proximal end begins at the superior aspect of the outflow tract of of the left ventricle, at the ventriculoaortic junction. 

The ascending aorta ends superiorly at an imaginary horizontal plane (blue dotted line) that passes through the sternal angle (of Louis), continuing distally with the aortic arch. This is an important anatomical landmark, as many surgeons use as the superior border of the ascending aorta an oblique plane that passes proximal to the brachiocephalic trunk (yellow dotted line). Although this landmark could be useful in surgery, it is not anatomically correct.

Since the sternal angle (of Louis) also indicates the superior border of the pericardial sac, it can be said that the ascending aorta is completely intrapericardial, and in surgery the pericardial sac should be the anatomical landmark used to separate the ascending aorta from the aortic arch.

From its point of origin at the ventriculoaortic junction, the aorta presents with a dilated region where the aortic valve is located. The aortic valve is one of the two  semilunar valves of the heart, and the dilation of this region is caused by the presence of the sinuses of Valsalva. This dilated bulbous segment is known as the aortic root.

Ascending aorta, anterior view
Ascending aorta. Click on the image for a larger version.
The dilated, sinus portion, or aortic root segment of the ascending aorta continues superiorly with the tubular portion of the ascending aorta. The area of transition between these two components is marked by a sharp crease known as the sinotubular junction (STJ). The dilation of the aortic root is caused by the presence of the sinuses of Valsalva, named after Antonio Maria Valsalva (1666 - 1723).

The tubular portion of the ascending aorta ascends with an inclination anteriorly and to the right. The ascending aorta presents with a slight anterior bulge causing the transverse section of this aortic segment to be slightly oval.

Only two arteries arise from the ascending aorta, both usually at the aortic root segment, just inferior to the STJ. These are the right coronary artery and the left coronary artery. There are anatomical variations where only one, or up to five different coronary arteries have been described.

Image property of:CAA.Inc.Artist:Dr. E. Miranda


Kernicterus is a disorder where excess bilirubin accumulates in the deep neural tissues of the brain and can cause brain damage in the newborn.

It is characterized by jaundice and a limpness of the newborn, devoid of energy. Can present with seizures, convulsions, and muscle spasms.

This condition is treatable and requires awareness from the parents if yellowness of the skin (jaundice) is detected along with the above-mentioned signs in the early days post-partum. There are other signs not mentioned in this article

The word [kernicterus] comes from the German word [kern], meaning “nucleus” or “core”. In this particular word the term kern refers to the fact that one of the most importantly affected brain structures in kernicterus are the basal ganglia of the brain (also known as the "central nuclei", found at the "core" of the brain. It also includes the word [icterus] from the Greek word [ικτερός] pronounced (ikterós). The word [icterus] in Greek was originally used to denote a yellow bird, and is now used to denote the yellow color of jaundice.

 Newborn with kernicterus jaundice
Click on the image for a larger version. 

We would like to thank diseasepictures.com for the image in this article. For additional information on neonatal jaundice, click here.

1. Clayman, L. "The AMA Encyclopedia of Medicine" 1989. Random House, NY
2. “The Origin of Medical Terms” Skinner HA 1970 Hafner Publishing Co.

Thanks to Jackie Miranda-Klein for her contribution suggesting this word. Please consider contributing to Jackie's medical mission to Belize by "clicking here".


The term [parenchyma] is a Greek term (παράένχέω). Its origin and meaning have little relation to the medical use of the term. The word means "that what is poured" or to "pour in". The actual definition of the term is "the proper mass of a solid organ". If someone refers to the "liver parenchyma", they are referring to the hepatic tissue, so it is with any other solid organ.

The etymology of the word is obscure and reflects ancient physiological theories and history. Vesalius mentions that the word was introduced by Erasistratus circa 300BC. He thought that the blood was "poured" into the organ and then this poured fluid would congeal to form the organ's proper mass. With time this concept was abandoned, but the word persisted to its modern meaning.

Interesting, there are many which accentuate the word wrongly. The accent or stress should be on the letter "e" and not on the letter 'y", so it should be pronounced "parénchyma"

Layers of the GI tract

The gastrointestinal (GI) tract is formed, with a few exceptions, by four concentric layers of tissue. These are, from deep to superficial, the mucosa, submucosa, muscular (or muscularis) and the serosa layers. This is the simplified version. The fact is that there are more sublayers.

The mucosa layer is characterized by the presence of intestinal villi, which in the stomach and small intestine contribute to absorption of the digested food. The mucosa has a thin layer of connective called the "lamina propia" and external to it a thin layer of smooth muscle, the muscularis mucosae.

Layers of the gastrointestinal tract
Images property of:CAA.Inc.Artist:Dr. E. Miranda
The submucosa layer is formed by irregular connective tissue and contains on its most external region a plexus of nerves and neurons, the "submucosal plexus of Meissner", which provides parasympathetic innervation to glands and the muscularis mucosae.

The muscular layer, also known as the "muscularis" is composed of two sublayers of smooth muscle. The deep layer contains circular fibers and is known either as the "circular muscle layer" or the "muscularis interna", the superficial layer contains longitudinal smooth muscle fibers and is known as the "longitudinal muscle layer" or the muscularis externa. Between both muscle layers lies the "myenteric plexus of Auerbach", a layer of sympathetic and parasympathetic nerves and neurons that provides nerve supply to the muscular layer. The combined action of this plexus on the muscular layer is responsible for peristalsis.

The serosa layer is the outer or external layer and is formed by a layer of peritoneum. As such, this layer can also be called "visceral peritoneum".

There are variations from GI organ to GI organ in the arrangement, content, glands, thickness of the layers, etc. The most important differences can be found in the thoracic esophagus and most of the rectum which are devoid of a serosa layer, and in the stomach, where there is a third muscular layer, deep to the circular layer, called the "oblique layer" that contributes fibers to the lower esophageal sphincter found at the esophagogastric junction.