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 view - Human embryo about eight and a half weeks old. Public domain
Lateral view - Human embryo about
eight and a half weeks old

(UPDATED) The term [ventral] arises from the Latin word [venter] and the root term [ventr-] meaning "belly" or "sac". The adjective [ventral] means "towards the front" , or "towards the belly side of the body". The term ventral therefore means "abdomen".

Many use the term [ventral] synonymously with "anterior"; although this is technically correct, the proper term to use when referring to the patient in the anatomical position should be "anterior". In embryology, since the embryo is curved, most of the anterior aspect of the embryo looks towards the abdomen, ergo ventral.

A ventral hernia is any herniation that occurs in the anterior aspect of the abdomen, including Spigelian hernias, omphaloceles, etc.

Other terms that arise from the same root term are [ventricle], meaning "little belly", or "little sac", and [ventricular], meaning "pertaining to a ventricle".

Note: A comment from my friend Dr. Elizabeth Murray

"My understanding of "anterior" means "in the direction of movement" for any given organism (and "posterior" means opposite the direction of movement for an organism). Thus, ventral does not ever change for any creature (vertebrate or even invertebrate), as it refers to a body part/surface.  But when considering two-legged and four-legged (or finned) creatures, you see the differences:  Ventral = anterior in us, but in a dog or fish ventral = inferior.

Ventral/dorsal refer to belly/back in any organism, and cranial/caudal refer to head-end and tail-end in any organism -- those four terms refer to body parts.  However, anterior/posterior refer to the way an organism moves in space, and superior/inferior refer to an organism's relationship to the earth/pull of gravity."

An interesting side note: The word [ventriloquist] arises from the root term [-ventri-] from the Latin [venter] and the suffix [-loquist], from the Latin [loquos] and [locutus], meaning "to speak", or "someone who speaks". The term [ventriloquist] means then "someone who speaks from the abdomen (or stomach)". We now know that this is not so, but that is what most people think a ventriloquist does!

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 by Henry Vandyke Carter, MD., courtesy of bartleby.com