Medical Terminology Daily - Est. 2012

Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community. 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

Jean George Bachman

Jean George Bachmann
(1877 – 1959)

French physician–physiologist whose experimental work in the early twentieth century provided the first clear functional description of a preferential interatrial conduction pathway. This structure, eponymically named “Bachmann’s bundle”, plays a central role in normal atrial activation and in the pathophysiology of interatrial block and atrial arrhythmias.

As a young man, Bachmann served as a merchant sailor, crossing the Atlantic multiple times. He emigrated to the United States in 1902 and earned his medical degree at the top of his class from Jefferson Medical College in Philadelphia in 1907. He stayed at this Medical College as a demonstrator and physiologist. In 1910, he joined Emory University in Atlanta. Between 1917 -1918 he served as a medical officer in the US Army. He retired from Emory in 1947 and continued his private medical practice until his death in 1959.

On the personal side, Bachmann was a man of many talents: a polyglot, he was fluent in German, French, Spanish and English. He was a chef in his own right and occasionally worked as a chef in international hotels. In fact, he paid his tuition at Jefferson Medical College, working both as a chef and as a language tutor.

The intrinsic cardiac conduction system was a major focus of cardiovascular research in the late nineteenth and early twentieth centuries. The atrioventricular (AV) node was discovered and described by Sunao Tawara and Karl Albert Aschoff in 1906, and the sinoatrial node by Arthur Keith and Martin Flack in 1907.

While the connections that distribute the electrical impulse from the AV node to the ventricles were known through the works of Wilhelm His Jr, in 1893 and Jan Evangelista Purkinje in 1839, the mechanism by which electrical impulses spread between the atria remained uncertain.

In 1916 Bachmann published a paper titled “The Inter-Auricular Time Interval” in the American Journal of Physiology. Bachmann measured activation times between the right and left atria and demonstrated that interruption of a distinct anterior interatrial muscular band resulted in delayed left atrial activation. He concluded that this band constituted the principal route for rapid interatrial conduction.

Subsequent anatomical and electrophysiological studies confirmed the importance of the structure described by Bachmann, which came to bear his name. Bachmann’s bundle is now recognized as a key determinant of atrial activation patterns, and its dysfunction is associated with interatrial block, atrial fibrillation, and abnormal P-wave morphology. His work remains foundational in both basic cardiac anatomy and clinical electrophysiology.

Sources and references
1. Bachmann G. “The inter-auricular time interval”. Am J Physiol. 1916;41:309–320.
2. Hurst JW. “Profiles in Cardiology: Jean George Bachmann (1877–1959)”. Clin Cardiol. 1987;10:185–187.
3. Lemery R, Guiraudon G, Veinot JP. “Anatomic description of Bachmann’s bundle and its relation to the atrial septum”. Am J Cardiol. 2003;91:148–152.
4. "Remembering the canonical discoverers of the core components of the mammalian cardiac conduction system: Keith and Flack, Aschoff and Tawara, His, and Purkinje" Icilio Cavero and Henry Holzgrefe Advances in Physiology Education 2022 46:4, 549-579.
5. Knol WG, de Vos CB, Crijns HJGM, et al. “The Bachmann bundle and interatrial conduction” Heart Rhythm. 2019;16:127–133.
6. “Iatrogenic biatrial flutter. The role of the Bachmann’s bundle” Constán E.; García F., Linde, A.. Complejo Hospitalario de Jaén, Jaén. Spain
7. Keith A, Flack M. The form and nature of the muscular connections between the primary divisions of the vertebrate heart. J Anat Physiol 41: 172–189, 1907.


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Lateral schematic view of the peritoneal membranes. Image modified from the original by Henry VanDyke Carter. Public Domain
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The [greater omentum] is a large, fatty apron-like structure that covers the abdominal viscera inferior to the greater curvature of the stomach. It is formed by a double peritoneal layer that contains fat, vessels, lymphatics, and nerves. This double peritoneal structure is continuous with the anterior and posterior serosal layers of the greater curvature of the stomach, drapes inferiorly, sometimes all the way to the pelvis and the folds upon itself posteriorly and superiorly ascending to become continuous with the anterior and posterior serosal layer of the transverse colon. Because it folds upon itself, the greater omentum can be considered to be a four-layered structure. See accompanying image.

The greater omentum contains vessels that arise from the right and left gastroepiploic arteries and veins as well as omental (epiploic) branches of the greater curvature vascular arcade.

The left border of the greater omentum reaches to the splenic hilum, while the right border extends as far as the pylorus and inferior aspect of the first portion of the duodenum. Because of its location, covering the intestines and its apron-like structure, the greater omentum is also known as the “surgeon’s apron”.

Abdominal dissection
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The term ‘abdominopelvic ligament” has been discussed in this article. The greater omentum has several “ligament” components that stretch between abdominal viscera. They are the:

• Gastrocolic ligament: Main portion of the greater omentum extending between the stomach and the transverse colon
 Gastrosplenic ligament: The portion of the greater omentum stretching between the stomach and spleen
• Splenorenal ligament: A continuation of the greater omentum stretching from the left kidney to the spleen.

As a side note, the lesser omentum (related to the lesser curvature of the stomach) contains less fat than the greater omentum.

First image(s) modified from the original by Henry VanDyke Carter. Public Domain
Second i
mage(s) property of: CAA.Inc.Photographer: D.M. Klein