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.

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 664 guests online


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.


 "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.com

 

 

Dissection of the abdomen. The greater omentum is being pulled anteriorly
Click for a larger image

UPDATED: The term [mesentery] is of Greek origin. The prefix [mes(o)-] arises from the Greek [μέσο] meaning "middle", the root term [-enter-] means "small intestine" or "intestine", and the suffix [-y] means "process" or "structure". Thus, the mesentery is "a structure in the middle".

The term [mesentery] can be used as a generic word to denote a double-layered peritoneal membrane that stretches between an abdominal viscus and the abdominal wall. A more precise use of the term is that of mesentery proper, which extends between the posterior abdominal wall and the jejunum and ileum. The superior mesenteric artery and veins are found at the root of the mesentery proper, along with a large accumulation of lymphatic nodes, and sympathetic and parasympathetic nerves.

Between the two layers of the mesentery proper, there are jejunal and ileal arteries and veins, a complex system of arterial and venous arches, as well as lymphatic vessels,  autonomic nerves, and varying degrees of fat. Because of the presence of the mesentery proper, the jejunum and ileum are mobile or intraperitoneal, that is, they can slither, turn and twist with the movements of peristalsis. This movement is helped by the presence of a small amount of peritoneal fluid.

Transillumination of the transverse mesocolon. Courtesy of Michiaki Akashi, MD
Click for a larger image

The fact that the mesentery is intraperitoneal is important in surgery. If the organ can already move around because of its mesentery, then it does not need to be "mobilized", it is already mobile!! If the organ (jejunum or ileum) have adhesions that limit their mobility within the abdominal cavity, the surgeon may have to perform and adhesiolysis to restore their mobility.

The first image shows an anatomical dissection where the greater omentum has been pulled anteriorly, exposing the small intestine and its mesentery, as well as the transverse mesocolon. Click on the image for a larger depiction. The second image (courtesy of Dr. Michiaki Akashi) is artwork depicting the surgical technique of transillumination, where the surgeon will shine a light through the mesentery to visualize the blood supply to the intestine prior to ligation and transection. The mesentery-like structure being transilluminated is the transverse mesocolon

WARNING: The first image is a photograph of a human dissection and can be considered descriptive.

NOTE: My personal thanks to Michiaki Akashi, M.D.for allowing us to use his artwork in this article. Dr. Akashi works as a surgeon and pathologist in the Saga Prefectural Hospital Koseikan in Saga, Japan.Dr. Miranda

First image property of: CAA.Inc. Photographer: David M. Klein