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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Interventricular septum

UPDATED: The prefix [inter-] means "between". The root term [ventricul-] refers to a ventricle, from the Latin [ventriculus], meaning "little sac" or "little belly". The word [septum] is Latin, and means "wall", "division", or "partition". The plural form for [septum] is [septa].

There are two septa in the heart. The interatrial septum (see superior image, item "E") is found between the atria, and the interventricular septum (see superior image, item "D"). The interventricular septum has two components, the muscular interventricular septum, and a small, superiorly situated membranous septum. The interventricular septum is quite muscular as seen in both images. Click on each image for a larger picture.

The cardiac interventricular septum receives blood supply from branches of both the right and left coronary arteries. The anterior 2/3rds of the interventricular septum receive blood supply through anterior septal perforators that arise from the left anterior descending artery (LAD), a branch of the left coronary arteryartery. The posterior 1/3rd of the interventricular septum receives blood supply by way of posterior septal perforators that arise from the posterior descending artery (PDA), a branch of the right coronary artery.

For a detail of the blood supply to the interventricular septum, click on the inferior image.

Heart model - LAO cranial viewInterventricular septum - short axis view of the heart
Superior image property of:CAA.Inc.. Photographer:D.M. Klein.
Inferior image modified from "Slide Atlas of Cardiac Anatomy" (out of print):Library catalog.