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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Infected Canal of Nuck Hydrocele, Mandhan, P; Bhatti, K.
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The "Canal of Nuck" is the patent embryological remnant of the processus vaginalis in the female. The processus vaginalis is an evaginated extension of the peritoneum that forms to the side of the gubernaculum, a small fibrous cord that is attached to the lower pole of the gonad in the embryo. On the other end, the gubernaculum attaches to the inner aspect of the labioscrotal fold, an embryonic structure that will become the scrotum in the male and the labia majora in the female.

In the male, the processus vaginalis accompanies the gubernaculum and the testicle, on its descent towards the scrotum. In the female, the gonad (ovary) stays in the pelvis and the embryological remnants of the gubernaculum become the proper ovarian ligament (uteroovarian ligament) and the round ligament of the uterus which enters the inguinal canal, splits into multiple small fibers that disappear in the tissues of the labium majus.

Infected Canal of Nuck Hydrocele, Mandhan, P; Bhatti, K.
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In the male (and female) the walls of the processus vaginalis normally fuse, closing the communication between the scrotum (and the labia majora) and the main peritoneal cavity. If they remain open, the name is different, although the pathological consequences are similar (hernia, cysts or hydrocele). In the male, it is called a “patent processus vaginalis”, and in the female it is called the “Canal of Nuck”, which is found patent in 10-20% of the cases, although its presence does not per se imply the presence of pathology.

It was first described by Anton Nuck, a Dutch surgeon and anatomist (1650-1692) in his book "Adenographia Curiosa & uteri foeminei anatome nova" published in 1691. In this book he questions why do some females present with inguinal hernias: "Haecce , praeter alias herniarium species , in utroque sexu obvias auditoribus meis anno fuperiori demonftrandi , difficile vifum fuit explicare , qui Hernia foeminarum inguinales orirentur?" Why when it is easy to see (the canal) in other species it is so difficult to explain to those listening why only some women have inguinal hernias?

Infected Canal of Nuck Hydrocele, Mandhan, P; Bhatti, K.
Click for a larger image

In figure XL of the same book he proceeds to show the open processus vaginalis which was from then on known as the eponymic "Canal of Nuck"

The images in this article are from “Case Report: Infected Hydrocele of the Canal of Nuck” by Mandahan, P and Batthi, K. (see sources) Figure 1 shows the superficial hydrocele herniation; figure 2 shows the infected hydrocele; and figure 3 shows the excised opened hydrocele. Read the full article here

http://dx.doi.org/10.1155/2013/275257

My personal thanks to Dr. Sanford Osher who suggested this article. Dr. Miranda