Angle of Louis - More Than Meets the Eye

Med Talks

by Nicole and Amanda Strickland, MS1

The Angle of Louis (Sternal Angle)

As we first-year medical students first learned in anatomy lab and then experienced in our Colleges sessions, clinicians use many anatomical landmarks to guide their physical exam of a patient. One such landmark is the sternal angle, a junction between the manubrium and body of the sternum (or “breastbone”).

The sternal angle is easily felt as a small protuberance on the upper part of the chest, and it marks the location of the second rib. From this location, a doctor can count ribs, know where to put his or her stethoscope to listen for specific heart sounds, and more.

Many anatomical landmarks are named after the person who first described them. For example, in our last article, we showed that the “ileocecal valve” is also known as “Tulp’s valve,” named after the Dutch anatomist Dr. Nicolaes Tulp.

Although the current trend in anatomy is to use the names that reflect the anatomy rather than the discoverer, some anatomical textbooks and atlases continue to list both sets of names. Such is the case with the sternal angle, which is called the Angle of Louis.

Naturally, this triggered our medical history detective instincts, and we had to find out — who was Louis? What we found went far beyond the breastbone and took us to the French Revolution.

The French surgeon Dr. Antoine Louis (1723-1792) was the secretary of the Royal Academy of Surgeons and is credited as being the technical inventor of the guillotine; in fact, the guillotine was initially known as the louisette. The device was soon renamed in honor of Dr. Joseph Guillotin (1738-1821), the doctor who strongly advocated for a “more humane” method of execution. Both doctors worked under the same royal committee that pushed for the guillotine to be used as the official execution method in France. Their efforts succeeded, and the guillotine quickly became the gruesome symbol of the French Revolution.

Returning to the sternum, we were amazed at how much we can learn from anatomy, both scientifically and historically. Besides discovering the name of a body part, we uncovered an inconspicuous yet fascinating facet of medical history. There is always more than meets the eye - every name has a story, and to truly appreciate those names beyond just pure memorization, we should learn those stories and tell others about them.

In many of our courses in medical school, professors not only teach us the science of medicine, but also introduce us to the history behind medical findings. Since there is not enough time during class, we would like to take these leads into medical history further and share what we have found on MedTalks.