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 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

Antoine Louis

French surgeon, anatomist, and physiologist. Following his medical studies and a long career as a physiologist, Antoine Louis was named Permanent Secretary of the Royal French Academy of Surgery. His other titles were those of Professor of the Royal Academy, Consultant Surgeon of the Armies of the King, member of the Royal Society of Sciences of Montpellier, Inspector of the Royal Military Hospitals, and Doctor in Law of the University of Paris. As a member of these academies Louis was instrumental in the design and construction of the guillotine. Initially called the "Louisette", this device was later named after another French physician in the same committee, Dr. Joseph-Ignace Guillotin.

Antoine Louis' name is better know to history as the eponymic origin of the "sternal angle" also know as the "Angle of Louis" and synonymously (probably by misspelling or translation) the "angle of Lewis", and "angle of Ludwig". This anatomical landmark is extremely important as it serves as a superficial landmark for important anatomical occurrences (click here).

As a point of controversy, there are some that contest the history of this eponym adjudicating it to Pierre Charles Alexander Louis (1787-1872), another French physician dedicated to the study of tuberculosis.

1. Srickland, N; Strickland A Angle of Louis, More Than Meets the Eye. MedTalks:
2. Ramana, R. K., Sanagala, T. and Lichtenberg, R. (2006), A New Angle on the Angle of Louis. Congestive Heart Failure, 12: 197–199
. "The origin of Medical Terms" Skinner, HA; 1970

 "Clinical Anatomy Associates, Inc., and the contributors of "Medical Terminology Daily" wish to thank all individuals who donate their bodies and tissues for the advancement of education and research”.

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Atrial fibrillation

What is atrial fibrillation?

Atrial fibrillation (AFib) is one of the most common heart conditions, affecting 4% of the adult population. Characterized by a rapid, irregular heartbeat, AFib is largely due to abnormal electrical impulses that cause the atria of the heart to quiver when it should be beating steadily. Blood flow is reduced and is not completely pumped out of the two small upper chambers of the heart, the atria.  This negatively impacts cardiac performance and also allows the blood to pool and potentially clot. At rest, a normal heart rate is approximately 60 – 100 beats per minute.  In a person with AFib, that heart rate can skyrocket to 180 bpm or even higher.  Thorough testing by your health care provider can spot abnormalities in the heart's rhythm before any obvious symptoms are noticed.

What are the symptoms?

EKG - Atrial Fibrillation, courtesy Dr. Randall K Wolf
Click on the image for a larger view

Whether it is caused by stress, exercise, or too much caffeine, most people experience a racing heart from time to time.  Most cases are harmless, but AFib is a serious medical condition that may often be long lasting.  Some people with AFib experience no symptoms at all.  But for others,  AFib may cause:

    Exercise intolerance
    Severe shortness of breath
    Chest pain

What causes atrial fibrillation?

Your heart is divided into four chambers: the two upper chambers called atria, and two lower chambers called ventricles. In order for blood to be pumped through your body, a group of specialized cardiac cells, the conduction system of the heart,  sends electrical impulses to the atria that tells your heart to contract. Contractions of the heart send approximately five quarts of blood through your body every minute. In people with AFib, however, the impulses are sent chaotically. The atria quiver instead of beat; the blood isn't completely pumped out and may pool and potentially clot.

Are you at risk?

Your chances of developing AFib increase with age.  AFib occurs more commonly in women than in men.  According to the Framingham Heart Study (http://circ.ahajournals.org/cgi/content/full/110/9/1042), AFib is associated with a higher risk of death for women than for men. You are also at greater risk of developing AFib if you suffer from an overactive thyroid, high blood pressure, a prior heart attack, congestive heart failure, valve disease or congenital disorders.


AFib can sometimes be diagnosed with a stethoscope during an exam by a doctor or other health care provider and is confirmed or diagnosed with an electrocardiogram (EKG). There are several types of EKG’s. They are:

Resting EKG – Electrical activity in the heart is monitored when a person is at rest.
Exercise EKG – Activity is monitored when a person jogs on a treadmill or exercises on a stationary bike.
24-hour EKG (Holter Monitor) – A person wears a small, portable monitor that detects activity over the course of a day.
Transtelephonic event monitoring – A person wears a monitor for a period of a few days to several weeks. When AF is felt, the person telephones a monitoring station or activates the monitor's memory function. This type of EKG is particularly useful in detecting AF that occurs only once every few days or weeks. Unfortunately this type of monitor does not record heart events while you are sleeping.

The image on this article is a typical EKG AFib recording showing the flutter of the atria followed by the ventricular contraction. In the larger image (click on the image of the article) you can see how this fluttering of the atria causes an abnormal spacing of the ventricular contractions which some patients feel in their chest.

PERSONAL NOTE:Dr. Wolf will lecture on a seminar on this topic on April 21st, 2018 in Houston, TX. For more information on this event and on AFib, click here.

Thanks to Dr. Randall Wolf for the image and links

An analysis of a letter from Dr. Ephraim McDowell (1829)

This article continues the musings of "Interesting discoveries in a medical book". In this book I found a copy of a letter written by Ephraim McDowell, MD; who on December 25, 1809 performed the first recorded ovariotomy in the world. The patient was Mrs. Jane Todd Crawford, who has also been the subject of several articles in this website, including a homage to the "unknown patient/donor".

The book seems to have belonged to Cecil Striker, MD, who practiced in Cincinnati. Dr. Striker was a faculty at the University of Cincinnati and one of the founders of the American Diabetes Association (ADA). He also was one of the first physicians to work in 1923 with a "newly discovered" drug by the Eli Lilly Company (Indianapolis) this drug was named Insulin. The medical application of Insulin had only just been discovered about a year earlier.

Inside the book there is a copy of a letter by Dr. Ephraim McDowell to Dr. Robert Thompson dated January 2nd, 1829, a year before Dr. McDowell's death. At the time (1829) Dr. Thompson (Sr.) was a medical student in Philadelphia. According to the note Dr. Thompson lived in Woodford County, KY, had three children and died in 1887. One of his children was also a doctor, but I have not been able to ascertain if this book was given to him by Dr. Striker.

The letter is shown in the image attached. In this letter Dr. McDowell describes in his own words the ovariotomy he performed on Jane Todd. He also describes other ovariotomies he performed and his opinion on "peritoneal inflammation".

Note how the letter has no paragraph separation. Apparently, at the time writing paper was expensive and the less pages used, the better! The text of the letter is as follows:

Danville, January 2, 1829

Mr. Robert Thompson
Student of Medicine
No. 59 Spruce Street
Philadelphia, Pennsylvania


Letter from Ephraim McDowell to Robert Thompson
Letter from Ephraim McDowell to Robert Thompson
Click on the image for a larger depiction

At the request of your father I take the liberty of addressing you a letter giving you a short account of the circumstances which lead to the first operation for diseased ovaria. I was sent in 1809 to deliver a Mrs. Crawford near Greentown of twins; as the two attending physicians supposed. Upon examination per vaginam I soon ascertained that she was not pregnant; but had a large tumor in the abdomen which moved easily from side to side. I told the lady that I could do her no good and carefully stated to her, her deplorable situation. Informed her that John Bell, Hunter, Hay, and A. Wood four of the first and most eminent surgeons in England and Scotland had uniformly declared in their lectures that such was the danger of peritoneal inflammation, that opening the abdomen to extract the tumor was inevitable death. But not standing with this, if she thought herself prepared to die, I would take the lump from her if she would come to Danville. She came in a few days after my return home and in six days I opened her side and extracted one of the ovaria which from its diseased and enlarged state weighed upwards of twenty pounds. The intestines as soon as an opening was made run out upon the table, remained out about twenty minutes and being upon Christmas Day they became so cold that I thought proper to bathe them in tepid water previous to my replacing them; I then returned them, stitched up the wound and she was perfectly well in 25 days. Since that time I have operated eleven times and have lost but one. I now can tell at once when relief can be obtained by an examination of the tumor if it floats freely from side to side or appears free from attachments except of the lower part of the abdomen. I advise the operation, having no fear from the inflammation that may ensue. I last spring operated upon a Mrs. Bryant from the mouth of the Elkhorn from below Frankfort. I opened the abdomen from the umbilicus to the pubis and extracted sixteen pounds. The said contained the most offensive water I ever smelt, and the attendants puked or discharged except myself. She is now living; from being successful in the above operation. Several young gentlemen with ruptures have come to me. I have uniformly cut the ring open, put the intestines up if down the cut the ring all around, every quarter of an inch then pushed the parts closely together and in every case the cure has been perfect. Therefore it appears to me a mere humbug about the danger of the peritoneal inflammation. Much talked about by most surgeons. After wishing you Health and Happiness,

I am yours sincerely
E. McDowell

P.S. Your father looks better than I have ever seen. Your sister is also in health

The most important point of this letter is how easily and publicly they name patients and their home addresses. Today this would be  a violation of the Health Insurance Portability and Accountability Act of 1996, commonly known as HIPPA, a legislation that provides data privacy and security provisions to safeguard patient medical information.

It is also interesting to see how Dr. McDowell explained to Mrs. Crawford how difficult and dangerous the procedure would be. He stated how four renown surgeons in England and Scotland said that opening the abdomen was "inevitable death". Another point was how long the intestines were outside the body ... twenty minutes, and the maneuver Dr. McDowell used to bring them back to normal temperature. Late December in Kentucky is quite cold, even with wooden stoves and such. I wonder how much the lower temperature helped the patient.

The last point refers to his success in hernia procedures in young males. In the 1800's the word "rupture" was the standard to name abdominal hernias. Without explaining the procedure in detail, Dr. McDowell says that "every cure has been perfect". At the time, this was unprecedented, as the recurrence of inguinal hernia procedures, when attempted, was close to 25%.

The house where Dr. McDowell lived and practiced is today a museum in Danville, KY. In February, 2017 I visited this museum and wrote an extensive article on it. I encourage those interested in the History of Medicine to visit the place.

Pes anserinus

UPDATED: [Pes anserinus] is the name given to a tri-flanged structure formed by the attachment of the flattened tendons of three muscles to the anteromedial surface of the superior aspect of the shaft of the tibia. The tendons correspond to the sartorius, the gracilis, and the semitendinosus muscles. The pes anserinus is related superficially to the the tibial insertion of the medial collateral ligament of the knee. 

There is a bursa deep to these tendons, the [bursa anserinus], which can be the cause of painful bursitis.

The term [pes anserinus] literally means “goose foot”, as early anatomists compared this structure to the foot of this bird. In Latin [pes] means “foot”, and [anserinus] or [anser] means “goose”.

Pes anserinus. Image courtesy of Primal Pictures
For other anatomical structures whose names are related to birds, click here.

Thanks to Jackie Miranda-Klein for suggesting this post. Jackie is studying for the Physician Assistant Master's degree at Kettering College. Dr. Miranda.

Image modified from the original: "3D Human Anatomy: Regional Edition DVD-ROM." Courtesy of Primal Pictures


The word [torus] is of Latin origin and refers to “a rounded protuberance or swelling”. In science, it refers to a doughnut-shaped structure (see image). It also refers to the rounded, bulging, and circular base component of a pillar, found between the square plinth and the main body of the pillar. The torus can be seen in Egyptian, Greek, and Roman style pillars.

The term is used in anatomy and medicine to denote normal or abnormal circular or semicircular protuberances, as in the case of the “torus tubarius”, a normal semicircular elevation found at the ostium of the auditory tube (of Eustachius) in the lateral walls of the rhinopharynx. The torus tubarius elevation is due to the presence of lymphoid tissue which can get inflamed.

Torus - By LucasVB [Public domain], via Wikimedia Commons
Click on the image for a larger view

Torus mandibularis. An exostosis that develops on the inner side of the mandible
Torus palatinus: a benign, small exostosis that appears in the midline of the hard palate

In orthopedics it is used to denote a compression fracture where the cortex of a long bone close to one of its epiphyses buckles under longitudinal (axial) compression. The look of the fracture is similar to the location of the torus in a pillar. An example of this is the torus fracture (also known as buckle fractures) in children.

The term [torulus] is related to [torus], as it means a “small torus” and it refers to a small elevation, which is synonymous with the word “papilla”. An example of this is the term torulus tactiles palmaris, referring to small elevations on the palms of the hand. Another related term is [torulosis], referring to a large number of small elevations or pimples.

The following images are of a Greek pillar taken in 2014 in Athens showing the location of the torus. The next image shows a torus fracture. The image is from www.kidsfractures.com/forearm/ and we thank them for sharing the image with us. This is a great site for information on fractures in children.

Greek pillar - Personal picture Athens 2014
Click on the image for a larger view

Torus fracture - www.kidsfractures.com/forearm/
Click on the image for a larger view

1. “Medical Meanings: A Glossary of Word Origins” Haubrich, WS. Am Coll Phys. Philadelphia 1997
2. “The Origin of Medical Terms” Skinner, HA 1970, New York. Hafner Publishing Company
3. “Taber’s Cyclopedic Medical Dictionary” 16th Ed. 1989. Philadelphia. FA Davis Company
4.  www.kidsfractures.com/forearm/

Torus image: By LucasVB [Public domain], via Wikimedia Commons

Thanks to Jackie Miranda-Klein for suggesting this post. Jackie is studying for the Physician Assistant Master's degree at Kettering College. Dr. Miranda.

Bicuspid aortic valve

The normal components of the aortic valve are part of the aortic root. The valve is composed of three leaflets, each of which are related to a sinus of Valsalva, and three interleaflet triangles. The anatomy of the aortic root, the aortic valve and the interleaflet triangles of the aortic root have been described in other articles in this website.

A bicuspid aortic valve (BAV) is probably the most common cardiac defect of congenital origin. The prevalence of BAV ranges from 0.9% to 2% in the general population with a 3:1 male-female ratio.

In spite of the anomaly, a BAV may achieve normal valvular function, but this probably does not last, as BAV tend to develop calcifications in the adult leading to valvular disease, dysfunction, valvar stenosis, so complications are common, the most common being dilation of the aortic root and ascending aorta.

Excised bicuspid aortic leaflets
Excised bicuspid aortic leaflets.
Click on the image for a larger version.
The etiology of a BAV is commonly accepted as congenital and there are some studies that demonstrate a familial component, but it can appear in families where there is no known history of BAV.

There are several attempts at classifying BAV, as the leaflets that fuse are different, and so is the way of fusion.

There is one rare BAV called “pure”. This purely BAV is a true BAV, composed of two leaflets of similar size where there is no clear fusion line or “raphe” between the fused leaflets (see image). This valve has two well developed interleaflet triangles and the third can be absent or vestigial.  The image depicts the excised calcified leaflets where the left and right coronary cusps are fused.  

Other types of BAV have a well-developed raphe, have two well developed interleaflet triangles and the third may be large or anomalous. The leaflets may also be asymmetrical. The classification of the different types of BAV goes beyond the objective of this article, but they can be studied in the references at the end of this article. There is no doubt that the different types of BAV can cause valvar disease and hemodynamic chaos, so the surgical approach for these may be different, including valve repair, aortic annuloplasty, interleaflet triangle remodeling, and of course valve removal and prosthetic implant, either biological or mechanical.

Clinically, the pathologies related to the function of the aortic valve are stenosis, valvular incompetence, and in some cases intimal aortic dissection, which is a catastrophic complication. Some of these complications are triggered by the calcification of the bicuspid leaflets. Interestingly, although BAV is a congenital disease, only one in fifty children known to have BAV have clinically significant disease by adolescence.

PERSONAL NOTE: I have permission to publish the image in this article… because the bicuspid aortic valve depicted in this article is my own. My personal thanks to the medical and support personnel at the Memorial Hermann Heart & Vascular Institute, in Houston, TX., and my three cardiovascular physicians without whom I would not be back writing this article, Drs. Randall K. Wolf (contributor to this website), Dr. William Ross Brown (cardiologist), and Dr. Tuyen Nguyen, who operated on me. Dr. Miranda.

1. “Etiology of bicuspid aortic valve disease: Focus on hemodynamics: Atkins, SA, Sucosky, P World J Cardiol. 2014 Dec 26; 6(12): 1227–1233.
2. “A classification system for the bicuspid aortic valve from 304 surgical specimens” Sievers, HH., Schmidtke, C. J Thorac Cardiovasc Surg 2007;133:1226-33
3. “Bicuspid Aortic Valve Disease” Siu, SC, Silversides, CK. JACC Vol. 55, No. 25, 2010:2789 – 800
4. “Bicuspid aortic valve aortopathy in adults: Incidence, etiology, and clinical significance” Int J Card 2015:1;400-407
5. ”Sutureless valve in freestyle root: new surgical valve-in-valve therapy” Villa E, Messina A  et al. Ann Thorac Surg  2013:96:e155–e157
6.” Sutureless aortic bioprosthesis valve implantation and bicuspid valve anatomy: an unsolved dilemma?” Lona, M, Guichard JB, et al Heart vessels 2016.31:1783-1789

Ligament of Treitz

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The ligament of Treitz is formed by a fold of peritoneum over the suspensory muscle of the duodenum. This muscle is also known as the "muscle of Treitz" or "musculus suspensorius duodenii". This muscle was first described in 1853 by Dr. Václav Treitz. 

The muscle (see image #1) has an unusual structure in that it is formed by a tendon with two muscular ends  of dissimilar embryological origin and function. The superior muscular component is skeletal (voluntary) muscle and arises as a slip of muscle (Hilfsmuskel) from the right esophageal crus of the respiratory diaphragm, as well as muscular and ligamentous fibers arising in the region of origin of the celiac trunk and superior mesenteric artery. The inferior portion of the muscle is smooth (involuntary) muscle and has been described as continuous with both the longitudinal and circular muscle layer of the intestine at the duodenojejunal junction.

Anterior view of the duodenum and the suspensory muscle of the duodenum
Click on the image for a larger version
Original image by Dr. Václav Treitz
The ligament of Treitz is an anatomical landmark used by anatomists and surgeons to denote the duodenojejunal junction and the point where the small intestine passes from retroperitoneal duodenum to intraperitoneal jeunum. Surgeons use the ligament of Treitz to measure the jejunum to decide where to perform an anastomosis.Click on the gray bar below the image to see the original sketch published by Dr. Václav Treitz in his 1853 publication "Ueber einen neuen Muskel am Duodenum des Menschens" (On a new muscle in the duodenum of man). The 'muscle of Treitz" is marked by an arrow.

It is important to clarify that the term "ligament" in the abdominopelvic cavity has a different meaning and structure from a skeletal ligament found in a joint. For more information click here.

Clinical anatomy, pathology, and surgery of the gastrointestinal tract are some of the many lecture topics developed and delivered to the medical devices industry by Clinical Anatomy Associates, Inc.

"Clinically Oriented Anatomy" Moore, KL. 3r Ed. Williams & Wilkins 1992
2. "The origin of Medical Terms" Skinner, AH, 1970
3. "The suspensory muscle of the duodenum and its nerve supply" Jit, I.; Singh, S. J. Anat. (1977), 123, 2, pp. 397-405
4. "Anatomical and functional aspects of the human suspensory muscle of the duodenum." Costacurta, L. Acta Anat (Basel). 1972;82(1):34-46
Image property of: CAA.Inc. Artists: Dr. E. Miranda and D.M. Klein