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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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UPDATED: The suffix [-(o)megaly] means "enlargement". It is related to the root term [-megal-], which is a derivate of the Greek word [μεγάλος] (megalos), meaning "large" or "big". The suffix component [-y] means "process". Usually used to refer to the abnormal or pathological enlargement of an organ.
Some applications of this suffix are:
- Cardiomegaly: Enlargement of the heart
- Splenomegaly: Enlargement of the spleen
- Lienomegaly: Enlargement of the spleen. the root term [-lien-] also means "spleen"
- Acromegaly: From the Greek prefix [acro-], meaning "top" or "extremity". Enlargement of the face, hands, and feet, caused by dysfunction of the hypophysis
- Hepatomegaly: Enlargement of the liver
Note: The links to Google Translate include an icon that will allow you to hear the Greek or Latin pronunciation of the word.
Thanks to our contributor Dr. Sanford Osher for inspiring this update.
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The prefix (sometimes used as a root term) [hydr-] has a Greek origin [υδωρο], meaning "water". It can be found in many common and scientific terms such as "hydrostatic", "hydroelectric", and "hydroplaning". It is also used in medical terms such as:
- Hydrocephalus: Literally "water in the head". Refers to a pathology where there is excess cerebrospinal fluid in the ventricular system of the brain
- Hydrocele: The suffix [-(o)cele] means "bulge" or "hernia". A watery mass or bulge, usually found in the scrotum.
- Hydrops or hydropsy: The excessive accumulation of serous fluid in a body cavity, such as ascites.
- Hydramnios: Excessive accumulation of fluid in the amniotic cavity during pregnancy
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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.
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
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The [lumbar triangle] is a well-defined triangular space in the posterolateral lumbar region. Also known as the inferior lumbar triangle, its boundaries are: inferior, the iliac crest; anteromedial: latissimus dorsi muscle; posterolateral: posterior border of the external oblique muscle. The triangle has a superior apex, and the floor of the triangle is the internal oblique muscle.
The triangle is named after Jean-Louis Petit (1674 - 1750), a French Surgeon who is said to have been an anatomy teacher at an early age and became a surgeon when he was only eighteen!
The lumbar triangle is an area that is not as thick as the rest of the abdominal wall and as such it is a site of potential weakness that can lead to a lumbar hernia, also known as Petit’s hernia.
Sources:
1. “Jean Louis Petit – A Sketch of his Life, Character, and Writings” Hayne, AP San Fran Western Lancet 1875 4: 446-454
2. “Oeuvres compl?tes de Jean-Louis Petit” 1837 Imprimerie de F. Chapoulaud
3. Extraits de l'eloge de Jean-Louis Petit Ius dans Ia seance publique de I' Academie Royale de Chirurgie du 26 mai 1750” Louis A. Chirurgie 2001: 126 : 475- 81
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The anatomical term [crista terminalis] is Latin. [Crista] refers to the crest of a helmet, a tuft (of hair or feathers), or a ridge. The word [terminalis] means "end" or "terminal". The term then means "the terminal or end ridge".
The crista terminalis is a superoinferior muscular ridge found in the right atrium marking the boundary between the smooth wall of the right atrium, also known as the "sinus venarum" (venous sinus), and the muscular wall of the right atrial appendage. The muscular wall of the right atrial appendage is comb-shaped and is called the pectinate muscle.
Because of the longitudinal direction of the muscular fibers of the crista terminalis, it is considered to be one of the internodal pathways for electrical transmission of the cardiac depolarization between the sinoatrial (SA) node and the atrioventricular (AV) node.
The crista terminalis causes a superoinferior longitudinal depression on the surface of the heart known as the sulcus terminalis.
The accompanying image is a dissection of a human heart and shows the crista terminalis, pectinate muscle, fossa ovalis, the ostium of the coronary sinus, the right atrial smooth wall of the sinus venarum. Click on the image for a larger version. The animated image does a slow pass trough all these and other structures.
Sources:
1. "The origin of Medical Terms" Skinner, AH, 1970
2. "Terminologia Anatomica: International Anatomical Terminology (FCAT)" Thieme, 1998
3. "Tratado de Anatomia Humana" Testut et Latarjet 8th Ed. 1931 Salvat Editores, Spain
Image courtesy of Rocky Vista University,College of Osteopathic Medicine, Parker, CO
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The word [carina] is Greek, from [καρίνα] meaning “keel”, as in the keel of a boat.
The carina is an anteroposterior elevation found at the point of bifurcation of the trachea into the left and right bronchi. When looking at it from the superior aspect, it does look as if you were looking at the keel of boat from the bottom up, and this is the image that endoscopists see when looking at this area. See the accompanying image.
The bifurcation of the trachea and the carina are usually found at the level of the sternal angle (of Louis), which is about the level of the superior border of the 5th thoracic vertebra.
Since the right bronchus is slightly wider than the left bronchus, the carina is usually slightly displaced to the left of the midline.
The lymph nodes that surround the area of the bifurcation of the trachea, and inferior to the bifurcation are called the carinal nodes.