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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Anterior view of the duodenum and the suspensory muscle of the duodenum
Click for a larger image

The ligament of Treitz is formed by a fold of peritoneum over the suspensory muscle of the duodenum. This muscle is also known as the "muscle of Treitz" or "musculus suspensorius duodenii". This muscle was first described in 1853 by Dr. Václav Treitz. 

The muscle (see the first image) has an unusual structure in that it is formed by a tendon with two muscular ends of dissimilar embryological origin and function. The superior muscular component is skeletal (voluntary) muscle and arises as a slip of muscle (Hilfsmuskel) from the right esophageal crus of the respiratory diaphragm, as well as muscular and ligamentous fibers arising in the region of origin of the celiac trunk and superior mesenteric artery. The inferior portion of the muscle is smooth (involuntary) muscle and has been described as continuous with both the longitudinal and circular muscle layers of the intestine at the duodenojejunal junction.

The ligament of Treitz is an anatomical landmark used by anatomists and surgeons to denote the duodenojejunal junction and the point where the small intestine passes from retroperitoneal duodenum to intraperitoneal jeunum. Surgeons use the ligament of Treitz to measure the jejunum to decide where to perform an anastomosis.

Original image of the "Muscle of Treitz"
Original image of the "ligament of Treiz"

There is much discussion today on eponyms, that is, associating an individual's name to an anatomical structure or surgical procedure. In spite of the pressure to make eponyms dissapear, the ligament of Treitz is here to stay!

The second image is a copy of the original image published by Dr. Václav Treitz in his 1853 publication "Ueber einen neuen Muskel am Duodenum des Menschens" (On a new muscle in the duodenum of man). The 'muscle of Treitz" is marked by an arrow.

It is important to clarify that the term "ligament" in the abdominopelvic cavity has a different meaning and structure from a skeletal ligament found in a joint. For more information click here. The term "Ligament of Treitz" refers to the fold of peritoneum that attaches to the posterior aspect of the abdominal and lines the "muscle of Treitz".

Clinical anatomy, pathology, and surgery of the gastrointestinal tract are some of the many lecture topics developed and delivered to the medical devices industry by Clinical Anatomy Associates, Inc.

Sources:
1. "Clinically Oriented Anatomy" Moore, KL. 3r Ed. Williams & Wilkins 1992
2. "The origin of Medical Terms" Skinner, AH, 1970
3. "The suspensory muscle of the duodenum and its nerve supply" Jit, I.; Singh, S. J. Anat. (1977), 123, 2, pp. 397-405
4. "Anatomical and functional aspects of the human suspensory muscle of the duodenum." Costacurta, L. Acta Anat (Basel). 1972;82(1):34-46
Image property of: CAA.Inc. Artists: Dr. E. Miranda and D.M. Klein