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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 [-esthesia] is Greek, arising from the word [αίσθηση] (a?sthi?si?) meaning "sensation". Some of the applications of the term are as follows:
Note: The links to Google Translate include an icon that will allow you to hear the Greek or Latin pronunciation of the word. |
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The term [ostium] is Latin and means "mouth" or "opening". The origin of the meaning of this term is debated and seems to come from the Latin term [os], meaning mouth. Latin derivatives of this term are [osculum] and [oscularetur]; "kiss" and "kissing", respectively. The plural form for ostium is [ostia]
There are several named ostia in the human body. An example is presented in the accompanying image, showing the ostium of the coronary sinus. Another example are the ostia of the coronary arteries found in the aortic valve (one of the semilunar valves)
Image property of: CAA.Inc.
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UPDATED: The brachiocephalic trunk (also known as the brachiocephalic artery) is the first branch that arises from the aortic arch. It is a short branch (1.2 - 1.5 cm in diameter and 2.8 - 3.5 cm in length)1 that ascends superiorly and to the right. It divides just posterior to the right sternoclavicular joint giving origin to the right common carotid artery and the right subclavian artery. The brachiocephalic trunk is a non-paired structure, as there is no contralateral homonymous structure. On the left side the left common carotid and the left subclavian arteries arise directly from the aortic arch.
The term brachiocephalic is mixed, formed by the Latin root [-brachi-] meaning "arm", the Greek root [-cephal-] meaning "head", the combining form '"o", and the adjectival suffix "ic". The brachiocephalic trunk provides oxygenated blood to the right side of the head and right upper extremity.
There is a common mistake perpetuated in many books. Many call this structure the "innominate artery". The term [innominate] means "without a name", and it does have one: brachiocephalic trunk. The aortic arch and its branches have many potential anatomical variations.
1. "Tratado de Anatomía Humana" Testut & Latarjet 8 Ed. 1943 Salvat Editores, Spain
Image property of: CAA.Inc.Artist: Victoria G. Ratcliffe
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UPDATED: The choroid plexuses are highly vascular structures situated in the ventricular system of the brain. They are formed by convoluted capillaries surrounded by modified ependymal cells. The choroid plexuses are responsible for the constant formation of the cerebrospinal fluid (CSF), as well as part of the blood-brain barrier, which in this case should probably be called the blood-CSF barrier.
The choroid plexuses are found in each ventricle of the brain. The accompanying image shows a dissection of a human brain where the frontal, parietal, and occipital lobes, as well as the corpus callosum have been removed to expose the lateral ventricles. The trigone has been transected and reflected posteriorly and the choroid plexuses can be seen as a cluster of grape-like longitudinal masses in each lateral ventricle.
Choroid plexuses form when three elements come in contact within the brain: pia mater, ependymal epithelium, and blood vessels. This only happens in the ventricular system of the brain.
The etymology (word origin) of the term [choroid] is a bit complicated. The suffix [-oid] means "similar to", while the root term [chor-] derives from the Greek word [χορίου] pronounced (joríu), meaning "dermis", "skin", or "membrane". The reason for the use of this term is that the Greek used the term "membrane" referring to the highly vascularized membranes that invest a fetus.
The term "plexus" means a "mesh", so the term [choroid plexuses] means "similar to the vascular membranes that invest a fetus"
Sources:
1. "Medical Meanings, A Glossary of Word Origins" Haubrich, W.S. 1997. American College of Physicians, Philadelphia, PA.
2. "Elementos de Neuroanatomia" Fernandez, J.; Miranda, EA.
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The term is formed by the prefix [ento- or -intu] from the Latin word [intus], meaning "within" and the Latin root term [-susscept-] meaning "to take, receive". In this usually intestinal pathology a proximal intestinal segment "pushes in" or is "taken in" by a distal segment. Because of adhesions or inflammation, an intestinal obstruction can ensue. This pathology can escalate causing localized ischemia and even necrosis with the potential of intestinal perforation. Intussuception is more prevalent in the ileocolic region and is the most common cause for intestinal obstruction in children aged 3 months to 6 years.
In an intussuscepted segment, there are two components: the intussusceptus (A), that is the proximal segment that protrudes into the distal segment; and the intussuscipiens (B), which is the distal segment, receiving the intussusceptus.
In the accompanying image, the arrow indicates direction of flow.
Image property of:CAA.Inc.Artist:Dr. Miranda
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The [scapula] is a flat, triangular bone that forms the posterior portion of the shoulder girdle. It is described with two surfaces, three borders, and three angles. The scapula attaches to the clavicle by way of the acromioclavicular joint and ligaments. Seventeen muscles attach to the scapula providing stability and movement to the upper extremity.
The scapula has three well-defined borders. The medial border (vertebral border) is slightly convex. The superior border has a notch, the scapular notch, and a bony protuberance called the coronoid process. Where the superior and the lateral border (axillary border) meet there is a bony protuberance (the glenoid process) which has a shallow depression (the glenoid cavity), site of the glenohumeral joint or shoulder joint. Also, the lateral border presents with a small bony process just inferior to the glenoid process, the infraglenoid tubercle.
The scapula has two well-defined angles, the inferior and the superior angle, while the lateral angle is less defined because of the presence of the glenoid process.
The surfaces or the scapula are the anterior and posterior surface. The anterior or costal surface is slightly concave, fairly smooth with some oblique ridges. Being concave, this area is known as the subscapular fossa. The posterior surface is separated in two by an oblique bony process call the spine of the scapula. The scapular spine ends superolaterally in a bony process called the acromion. Also, the spine of the scapula divides the posterior surface of the scapula into a supraspinous fossa and an infraspinous fossa.
The image is an anterior view of the left scapula. Image in Public Domain, by Henry Vandyke Carter, MD - Gray's Anatomy