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

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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Fossa Ovalis

[UPDATED] Latin words meaning "oval fossa" or "oval depression". The fossa ovalis is, as it names implies, an oval-shaped depression in the interatrial wall of the right ventricle. (see image, pointer "A"). The fossa ovalis represents in the adult the fetal communication between the right and left atrium allowing for fetal oxygenated blood to bypass the pulmonary circulation and enter the systemic circulation directly. The fossa ovalis is closed upon birth by two opposing membranes, and the higher pressure on the left side of the heart.

The persistence of the communication between the right and left atrium is known as an Atrial Septal Defect (ASD) and will need surgical correction. Some anatomists refer to this depression as the "foramen ovale" and it is surrounded by a well-defined muscular border known as the "limbus fossa ovalis", also known by the eponym "ring or anulus of Vieussens"

Fossa Ovalis [A]
The interatrial opening in the fetus, and the persistent ASD in the adult is referred by the eponym "the foramen of Botallus", remembering Leonardo Botallus (1530 - ??)

For more information: 

• On fetal circulation
• On the fossa ovalis (Gray's Anatomy)
• Image of the fossa ovalis (Gray's Anatomy)