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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Retroperitoneal organs
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The duodenum is a mostly retroperitoneal organ, part of the digestive tract, and the most proximal portion of the small intestine. This organ is approximately 10 inches in length (24.5 cm). It starts at the pylorus of the stomach, has a "C" shape, curving around the head and the neck of the pancreas, to end at the duodenojejunal junction.

The duodenum is described as having four segments of differing length, usually named numerically:

  • First segment: about two inches in length, it is dilated and called the "duodenal ampulla", or "superior duodenum"
  • Second segment: about three inches in length, it receives bile and pancreatic juice through the hepatopancreatic ducts and ampullae. It is also called the "descending duodenum"
  • Third segment: about four inches in length, it crosses the midline, and is also known as the "horizontal" or "transverse duodenum"
  • Fourth segment: one inch in length, this is the shortest segment, it ascends towards the duodenojejunal junction, which is tethered to the diaphragm by a fold of peritoneum around a fibromuscular band called the "ligament of Treitz". At this point the retroperitoneal duodenum becomes the intraperitoneal jejunum. This fourth segment is also called the "ascending duodenum"

The name of the organ is interesting. Most textbooks claim that is originates from the Latin [duodeni], meaning "twelve". The fact is that the duodenum was originally named in Greek [δώδεκα δάχτυλαν] meaning "twelve fingers". If you place both your hands together and add 1/4 of an inch to each side (as if you had an extra finger on each hand) that measures approximately 10 inches. The term was shortened by an incorrect translation to "twelve" by Gerard of Cremona (1114 - 1187) who called it "duodenum", a bad translation, as twelve fingers in Latin is [duodecim digitorum].

While most of the duodenum is retroperitoneal, the first inch of the superior duodenum (first segment) is intraperitoneal as it shares a small portion of the lesser omentum with the stomach and liver.

Sources:
1.
"Clinically Oriented Anatomy" Moore, KL. 3r Ed. Williams & Wilkins 1992
2. "The origin of Medical Terms" Skinner, AH, 1970 
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