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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Inferior surface of the liver. The gallbladder is depicted in green.. Public domain
Inferior surface of the liver

The [gallbladder] is a bile transient storage organ, part of the hepatobiliary tree, situated in the anteroinferior aspect of the liver. The gallbladder is found in a depression on the inferior aspect of the right lobe of the liver, the gallbladder fossa or fossa vesicae felleae.

In the gallbladder we describe its dome-shaped fundus, the body of the organ, and the neck which is the area that opens into the cystic duct. Close to the neck, the gallbladder has a small pouch (Hartmann's pouch) which is important for surgeons during a laparoscopic cholecystectomy, as this is where they will lock one of the instruments that allows them to manipulate the gallbladder for dissection of the organ from the gallbladder fossa (the gallbladder bed). The other surgical grasper is placed at the gallbladder fundus.

The gallbladder is composed by three layers. From deep to superficial they are:

• Mucosa: Characterized by a columnar epithelium. Towards the neck of the gallbladder the mucosa creates spiral ridges that continue in to the cystic duct.
• Fibromuscular layer: This layer is composed by connective tissue and smooth muscle, mostly longitudinal
• Serosa: This is an incomplete layer and is formed by visceral peritoneum covering the area of the gallbladder not in contact with the liver. 
In an unusual anatomical variation, the serosa layer can be almost complete, forming a pseudomesentery that may contains some veins.

The gallbladder receives its blood supply by way of the cystic artery, a branch of the right hepatic artery. The venous return is by way of multiple small veins that empty into the liver venous system. In some cases, these veins may form large sinuses between the liver and the gallbladder causing potential troublesome bleeding during a cholecystectomy. For those who like medical history, Dr. Eric Muhe performed the first laparoscopic cholecystectomy on September 12, 1985! We are but a few days from the 30th anniversary!

For more information on terminology on "gall-", "bile", "chol", and "chole", click here.

Sources:
1 "Tratado de Anatomia Humana" Testut et Latarjet 8 Ed. 1931 Salvat Editores, Spain
2. "Anatomy of the Human Body" Henry Gray 1918. Philadelphia: Lea & Febiger
Image modified by CAA, Inc. Original image courtesy of bartleby.com