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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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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![Coronary Arteries. The [*] indicates the left coronary artery](/images/MTD/LargeImages/coronaryarterieslabels_lg.jpg "Coronary Arteries. The [*] indicates the left coronary artery")
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UPDATED: The [anterior interventricular artery] is one of the two branches of the left coronary artery, the other one being the circumflex artery (CFX). Although the name "anterior interventricular artery" is the anatomical name, this artery is most commonly known by its clinical name, the [left anterior descending artery], or LAD.
The LAD lies deep to the epicardium in the subepicardial fatty layer. It gives off several important branches, including one or two (sometimes three) large diagonal arteries that provide blood supply to the anterior aspect of the left ventricle. Also of importance, the LAD provides several septal perforator arteries that provide blood supply to the anterior 2/3rds of the interventricular septum.
Because of the extensive arterial territory of the LAD, and its involvement with the left ventricle and the interventricular septum, the LAD is sometimes called by a non-clinical term: "the widow-maker".
There can be interesting anatomical variations in the coronary arteries of the heart. For a detail on these anatomical variations, click here. Heart and coronary artery anatomy is one of the many lecture topics presented by CAA, Inc
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UPDATED: The prefix [inter-] means "between". The root term [ventricul-] refers to a ventricle, from the Latin [ventriculus], meaning "little sac" or "little belly". The word [septum] is Latin, and means "wall", "division", or "partition". The plural form for [septum] is [septa].
There are two septa in the heart. The interatrial septum (see superior image, item "E") is found between the atria, and the interventricular septum (see superior image, item "D"). The interventricular septum has two components, the muscular interventricular septum, and a small, superiorly situated membranous septum. The interventricular septum is quite muscular as seen in both images. Click on each image for a larger picture.
The cardiac interventricular septum receives blood supply from branches of both the right and left coronary arteries. The anterior 2/3rds of the interventricular septum receive blood supply through anterior septal perforators that arise from the left anterior descending artery (LAD), a branch of the left coronary artery.
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The posterior 1/3rd of the interventricular septum receives blood supply by way of posterior septal perforators that arise from the posterior descending artery (PDA), a branch of the right coronary artery.
For a detail of the blood supply to the interventricular septum, click on the inferior image.
Superior image property of: CAA.Inc. Photographer: D.M. Klein.
Inferior image modified from "Slide Atlas of Cardiac Anatomy" (out of print): Library catalog.
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From Latin, meaning “opposite to”. This term has been used since the late 1700’s in English literature to denote “the lowest point”.
This term will be of interest as we study the anatomy of the aortic valve and aortic root.
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UPDATED: This word has a Greek origin from the term [ανεύρυσμα], composed of [ana] meaning "complete or throughout", and [eurus] meaning "wide", a "complete widening or dilation". It is used to refer to the dilation of an artery. Aneurysms can be formed in any artery, although they have some preferred sites. The most common aneurysms are found in the aorta, arterial circle of Willis, the root of the cerebral arteries, and internal carotid arteries.
Biomechanical studies suggest that once an aneurysm forms it will generally progress in its dilation until aneurysmal rupture. Because of turbulent flow within the aneurysm large clots are usually formed, which in turn can cause emboli.
The image shows an excised infrarenal abdominal aortic aneurysm (AAA). The two common iliac arteries can be seen. If you click on the image you will be able to see the same aneurysm opened through its posterior wall and the clot that was contained inside.
Since the definition of [aneurysm] is "a dilation of an artery", it is wrong to refer to the dilation of a vein as a "venous aneurysm. The proper term to refer to the dilation of a vein is [varix].
Image property of: CAA.Inc. Photographer: David M. Klein
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The [leg] is the anatomical region found between the knee joint superiorly and the ankle inferiorly. It contains two bones, the tibia and the fibula (os peroneus).
Since the Latin word [crus] means “pillar” or “leg”, the term [crural] is sometimes used to denote the leg region.
The wrong usage of the term [leg] to refer or denote all of the lower extremity is one of my pet peeves. There are many health care professionals who use this term wrongly and are therefore forced to use the terms “upper leg” to refer to the thigh, and “lower leg” to refer to the leg proper.
The posterior compartment of the leg contains the soleus and gastrocnemius muscles which cause a superficial elevation known as “the calf”. The Latin term [suram] means “calf”, so the term [sural] can be used to denote the posterior aspect of the leg.
The anterior aspect of the leg is marked by the bony anterior tibial crest or shin, a word that is sometimes wrongly used to mean “leg”.
Original image courtesy of Connexions (http://cnx.org) [CC-BY-3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons
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Although this article is called “How to Read Medical Terms”, a better title would have been “How to Translate Medical Words” because that is what we do, we translate terms which have multiple linguistic origins to vernacular English.
Medical words are not read as we normally read English, from left to right. Rather, they are read in an order related to their components, prefixes, root terms, suffixes, and combining vowels.
Let’s take as an example the word [preperitoneal], where the prefix is [pre-], the root term is [-periton-] and the suffix is [-eal]. Read in normal left to right English the word would translate as “anterior (aspect of) peritoneum pertaining to”, which does not sound correct.
The proper way is to read the suffix first, the prefix second, and the root term last. Thus, this translation would read as “pertaining to (the) anterior (aspect of) the peritoneum”. There are exceptions of course, but the rule presented here applies to most medical words.
In the absence of the prefix, the word is translated suffix first and root term second.
When a word contains combined root terms they are read in the way they are written, from left to right, as they will have already been placed in a proximal to distal relationship, otherwise the word would be wrongly constructed.
There are more nuances to Medical Terminology, but they go beyond the objectives of "Medical Terminology Daily". For a complete course on Medical Terminology for your company, contact CAA, Inc.
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