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.

Click on the link below to subscribe to the MTD newsletter. If you think an article could be interesting to somebody else, click on the mail link at the top of each article to forward it. 

You are welcome to submit questions and suggestions using our "Contact Us" form. The information on this blog follows the terms on our "Privacy and Security Statement"  and cannot be construed as medical guidance or instructions for treatment. 

We have 93 guests and no members online

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”.

Click here for more information

abebooks banner

bookplateink banner


Hesselbach's triangle

Hesselbach’s triangle is a triangular region in the lower posterior aspect of the anterior abdominal wall (see yellow inset in the image). It is bound medially by the lateral border of the rectus abdominis muscle, superolaterally by the inferior (deep) epigastric vessels (label “C”) and by the inguinal ligament inferolaterally.

Hesselbach’s triangle is described as the area where a direct inguinal hernia will extrude from posterior to anterior, to protrude directly (hence the name) through the external (superficial) inguinal ring.

Franz Kaspar Hesselbach (1759-1816) was a German surgeon and anatomist who described inguinofemoral hernias in detail, publishing several books on the subject. His name is attached to several regions and structures:

• Hesselbach’s triangle, described in this article

• Hesselbach’s fascia. Known as the cribriform fascia, this perforated fascia covers the saphenous opening in the superior femoral region.

Posterior view of the abdominal wall. Hesselbach's triangle
• Hesselbach’s ligament. Also known as the interfoveolar ligament, this is a thickening of the transversalis fascia in relation to the inferior (deep) epigastric vessels. 

If you click on the picture, an original image by Hesselbach will appear. This image shows a defect in Hesselbach’s triangle, setting the stage for a direct inguinal hernia, as well as the interfoveolar ligament. Incidentally, Hesselbach's triangle as described today is not the area described originally by Dr. Hesselbach, where the lower border of the triangle was Cooper's ligament.

Initial image property of: CAA.Inc.Artist: M. ZuptichSecondary image by F.K. Hesselbach.

Clinical anatomy of the inguinofemoral hernias, as well as abdominal and perineal hernias are some of the lecture topics developed and delivered to the medical devices industry by Clinical Anatomy Associates, Inc.