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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This article is part of the series "A Moment in History" where we honor those who have contributed to the growth of medical knowledge in the areas of anatomy, medicine, surgery, and medical research.

Giulio Cesare Aranzio (Arantius)
Arantius

Giulio Cesare Aranzio (1530 -1589) Italian surgeon and anatomist. Born in Bologna, Giulio Cesare Aranzio is better known by the Latinized version of his name Julius Caesar Arantius. His Italian last name is sometimes spelled Aranzi.

Born in a poor family, Aranzio began his medical studies under the tutelage of his uncle, Bartolommeo Maggi (1477 – 1552), studied medicine at the University of Bologna where he graduated MD in 1556. The same year he became a Professor of Anatomy and Surgery at the in 1556. Arantius was the first lecturer at the University of Bologna to hold a separate professorship of anatomy. Before him, the University would allow any surgeon to perform dissection and lectures.

Arantius had several publications that include:

Observationes Anatomicas (Anatomical Observations)
De Humano Foetu  Opusculum (On the Human Fetus)
De Tumoribus Secundum Locos Affectos (Tumors according to the affected places)
Hippocratis librum de vulneribus capitis commentarius brevis (Short commentary on Hippocrates’ book on head wounds)

Arantius was the first to describe the foramen ovale (fossa ovalis) and the ductus arteriosus, discoveries that were later erroneously ascribed to Leonardo Bottalus (Botal). He also described the nodules in the leaflets of the aortic valve that today bear his name (nodules of Arantius) which he described as being “cartilaginous” in nature. This is not as farfetched as it seems as these nodules can become hypertrophic and harden with age. Arantius was also the first to describe the hippocampus, a formation on the brain associated with the limbic system, mood disorders, and depression.

Arantius was a consummate anatomist and a great surgeon. Apparently he treated nasal polyps, performed nasal reconstructions and a number of surgeries ahead of his time. One of his great anatomical observations was that the blood in the heart did not pass through “invisible pores” in the interventricular septum, but rather exits the heart through the pulmonary trunk, setting the stage for the discovery of circulation by William Harvey (1578 – 1609)

We have not been able to find a portrait of Arantius and the only reference is a  a bust with the name “Aranzio” located at the Biblioteca comunale dell'Archiginnasio in Bologna, Italy. The bust is found in the anatomical amphitheater, built in 1637. Unfortunately, the theater was severly damaged in January 29, 1944 during WWII. It has been meticulously restored over the years. Here is an article (in Italian) on the amphitheater.

Sources:
1. “Giulio Cesare Arantius (1530-1589): a surgeon and anatomist: his role in nasal reconstruction and influence on Gaspare Tagliacozzi” . Gurunluoglu R, Gurunluoglu A Ann Plast Surg. 2008 Jun;60(6):717-22
2. “Giulio Cesare Aranzio (Arantius) (1530-89) in the pageant of anatomy and surgery” Gurunluoglu R, Shafighi M, Gurunluoglu A, Cavdar S. J Med Biogr. 2011 May;19(2):63-9
3. “Hippocampus – Why is it studied so frequently?” Radonjic, V. et al Vojnosanit Pregl 2014; 71(2): 195–201
4: “The history of Bologna University's Medical School over the centuries, A Short Review” Moroni, P. Acta Dermatoven APA Vol 9, 2000, No 2 73-75