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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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The chordae tendineae, as their Latin name suggests, are tendinous cords found in the right and left ventricles of the heart. These chordae tendineae connect the papillary muscles to the leaflets of the atrioventricular (AV) valves. The vernacular term for these structures is "heart strings".
The function of the chordae tendineae is to limit the freedom of motion of the cusps of the AV valves (tricuspid and mitral), limiting their capacity to "flap" back into the corresponding atrium. Rupture of one or more chordae can cause retrograde flow (reflux or regurgitation) of blood from the ventricle into the atrium, causing cardiac dysfunction.
The chordae tendineae are part of a larger complex of interacting anatomical structures that include the fibrous "skeleton of the heart", the fibrous core of the AV valves, the chordae tendineae, the papillary muscles, and the complex fibrous internal structure of the papillary muscles and the ventricular wall.
The image shows the dissection of a human heart, with the right atrium open. The fan-like shape of the many chordae tendineae is clearly visible, spanning two leaflets. Observe that some chordae tendineae arise directly from the interventricular septum. These are known as the "septal chordae tendineae". Observe the atrioventricular sulcus, and the cardiac apex.
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The [common hepatic duct] is one of the components of the extrahepatic hepatobiliary tree that takes bile produced in the liver and transports it to the duodenum, with a storage function in the gallbladder.
The common hepatic duct (CHD) is formed by the junction of the right and left hepatic ducts which bring bile from the right and left functional lobes of the liver respectively. These hepatic ducts converge forming an obtuse angle.
During its trajectory the CHD is found between the layers of the lesser omentum. It has anatomical relations with the proper hepatic artery and the portal vein.
The CHD has an average diameter of 4 to 5 mm and an average length of 3cm (Testut & Latarjet 1931). It ends at the point of origin of the cystic duct which takes bile to the gallbladder. The CHD continues with the common bile duct, which empties into the second portion of the duodenum through the hepatopancreatic ampulla, also known as the Ampulla of Vater.
As with all the components of the hepatobiliary tree, the CHD presents with many anatomical variations. In cases the CHD has been reported with a length of 42 mm, and as short as 3 mm.
Following is the key to the image: 1. Bile ducts: 2. Intrahepatic bile ducts 3. Left and right hepatic ducts, 4. Common hepatic duct 5. Cystic duct 6. Common bile duct 7. Ampulla of Vater 8. Major duodenal papilla 9. Gallbladder 10–11 Right and left lobes of liver 12. Spleen. 13. Esophagus 14. Stomach Small intestine: 15. Duodenum, 16. Jejunum 17. Pancreas: 18: Accessory pancreatic duct, 19: Pancreatic duct. 20–21: Right and left kidneys (silhouette). The anterior border of the liver is lifted superiorly (brown arrow). Gallbladder in longitudinal section, pancreas and duodenum in frontal section. Intrahepatic ducts and stomach in transparency.
Sources:
1. "Tratado de Anatomia Humana" Testut et Latarjet 8 Ed. 1931 Salvat Editores, Spain
2. "Gray's Anatomy" 38th British Ed. Churchill Livingstone 1995
Original image (Public domain) by Jmarchn (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons
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The simplest definition of the prefix [pro-] is that it means “forward”. The truth is quite more complicated.
This prefix, used in vernacular English, actually has two different origins and meanings. One arises from the Latin [pro], meaning “on behalf of”, or “in favor of”, and as such we see it in the words proactive, pro-independence, and prohibition.
The second meaning comes from the Greek [πρό] (pr?) meaning “before” and “fore”. This evolved into “in front of” and later to “forward”, which is the main meaning used in medical terminology, as in the words prognosis and prolapse.
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The root term [-gnath-] arises from the Greek word [γνάθος] (gn?thos) meaning “jaw” or “jaw bone”. It is used in medical terms referring to jaw pathology,
- Prognathism or prognathia: The prefix [pro-] means “forward”. A protrusion of the jaw
- Retrognathism or retrognathia: The prefix [retro-] means “posterior”. A posterior displacement caused by lack of development of the jaw
- Micrognathia: The prefix [micro-] means “small”. A small jaw
All these words (prognathism, retrognathism, and micrognathism) are examples of dysmorphism. The accompanying image shows a case of acromegaly with consequent prognathism due to overdevelopment of the jaw.
Note: The links to Google Translate include an icon that will allow you to hear the pronunciation of the word.
Image: By Philippe Chanson and Sylvie Salenave [CC BY 2.0 (http://creativecommons.org/licenses/by/2.0)], via Wikimedia Commons
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UPDATED: The word [sphincter] derives from the Greek [σφιγκτήρ] (sfinkt??r), with the same meaning, in turn arising from the Greek word [σφιχτός] (sficht?s) meaning "tight". . The term was originally used by Galen (129AD - 200AD) in the meaning of "to bind tight" or "that which binds tight".
A sphincter is an area of circular muscle fibers that controls a canal or an opening. Rufus named some of them, because of their shape, [orbicularis], a Latin term meaning "circular". An example of this nomenclature are the [orbicularis oculi] and the [orbicularis ori] muscles, the circular muscles of the eye and mouth, respectively.
Some of the so-called "sphincters" in the body are functional sphincters, that is, they control a canal mostly because of their shape, not because of the constrictive action of their circular muscle fibers, such as the ileocecal sphincter or valve, which is normally a one-way valve or a check-valve (shown in the picture)
Other sphincters are true anatomical sphincters, where the number and strength of their circular fibers close off the lumen of the organ, but these are not one-way valves. An example of this type of sphincter is the pylorus.
Images and links public domain, courtesy of: www.bartleby.com
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UPDATED: The abdominal aorta is the fourth, last, and most distal portion of the aorta. It begins when the descending aorta passes through the aortic hiatus of the respiratory diaphragm, just about the level of the 11th or 12th thoracic vertebra. It ends inferiorly at the bifurcation of the aorta, anterior to the lower portion of the body of the 4th lumbar vertebra where the abdominal aorta is continuous with the right and left common iliac arteries.
The abdominal aorta gives off a number of paired (bilateral) and unpaired (single) arterial branches. The paired branches are:
• Inferior phrenic arteries: provide blood supply to the respiratory diaphragm
• Renal arteries: Provide blood supply to the kidneys
• Gonadal arteries: Depending on the gender, they are called testicular or ovarian arteries, providing blood supply to the gonads
• Lumbar arteries: There are four pairs of lumbar arteries, which pass posteriorly around the vertebral bodies and provide supply to the spine and the back.
• Suprarenal arteries: These are several minute arteries that provide blood supply to the suprarenal glands. The suprarenal (adrenal) glands also receive several minute arteries that arise from the renal arteries and the inferior phrenic arteries.
The unpaired arterial branches of the abdominal aorta are:
• Celiac trunk: Provides blood supply to the stomach, spleen, liver, and duodenum
• Superior mesenteric artery: Provides blood supply to duodenum, jejunum, ileum, and the right side of the colon
• Inferior mesenteric artery: Provides blood supply to the left side of the colon, and superior aspect of the rectum
• Middle sacral artery: This is the only branch of the aorta that arises from its posterior aspect, it descends providing blood supply to the sacrum and fifth lumbar vertebra
Clinically, the abdominal aorta is divided by the origin of the renal arteries into a suprarenal and an infrarenal segment. This division is important for the surgical treatment of abdominal aortic aneurysms (AAA). To see a AAA, click here.
The suprarenal segment is bound laterally by the crura of the respiratory diaphragm. and its inferior boundary is the superior aspect of the highest renal artery (usually the left renal artery). It has branches that are critical for the blood supply of most of the digestive tract, the celiac trunk and the superior mesenteric artery, plus the inferior phrenic arteries and the suprarenal arteries.
The infrarenal segment includes the renal arteries, the inferior mesenteric artery, gonadal arteries, lumbar arteries, and the middle sacral artery.
Image property of:CAA.Inc.Artist:Victoria G. Ratcliffe