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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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From the Latin [vena], meaning "vein". Some early authors postulated that the term derivates from the Latin word [venio] meaning "to come", because the blood in the veins "comes in" to the heart. There are two root terms meaning "vein", the first is the Latin derivated [-ven-], as in the terms venous and intravenous. The second root term is Greek [-phleb-], as in the terms phlebectomy, phlebotomy, and phlebotomist. Peripheral veins have internal one-way valves, while most of the central veins (in the trunk) do not present with valves. Failure of a peripheral venous valve can lead to dilation of the vein, condition called a varix.
- Venous: pertaining to a vein
- Intravenous: inside or within a vein
- Phlebectomy: removal of a vein
- Phlebotomy: to open a vein
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The term [carotid] is Greek and means "to sleep", "to stupefy", or "to put to sleep". This arises from the observed fact that compression of the large arteries in the neck caused animals to fall asleep (Rufus of Ephesus c.100BC). Andrea Vesalius proposed the name "soporalis arteriae", but the Greek term [carotid] is what we use today.
The carotid arterial system is bilateral. On the right side, the right common carotid artery arises from the brachiocephalic trunk, while on the left side the left common carotid artery arises from the aortic arch. The common carotid artery divides into an external and an internal carotid artery. The internal carotid artery presents a dilation close to its origin, the carotid sinus, and then heads superiorly to enter the carotid canal of the temporal bone. The internal carotid artery does not give any branches in the neck region and ends providing important branches to the eye and the arterial circle of Willis, which supplies part of the brain.
The external carotid ends giving origin to two arteries, the superficial temporal artery and the maxillary artery. The external carotid artery gives off six named branches:
• Superior thyroid artery
• Lingual artery
• Facial artery
• Ascending pharyngeal artery
• Occipital artery
• Posterior auricular artery
Sources:
1. "The ancient Hellenic and Hippocratic origins of head and brain terminology" Panourias IG, et al Clin Anat 2012 Jul;25(5):548-581
2. "The origin of Medical Terms" Skinner, AH, 1970
Images property of: CAA.Inc. Artist: Dr. E. Miranda
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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.
Prof. Wilhem-Conrad Roentgen
Wilhelm Konrad Roentgen (1845 - 1923). A German physicist, Professor Roentgen started studying Physics at the University of Ultrech, and receiving his degree from the University of Zurich. Having observed fluorescence on a paper covered with barium platinocyanide close to an active cathode ray. Suspecting the presence of "invisible rays", he devised an experiment to prove this.
On November 8, 1895 he confirmed his theory and called these invisible-to-the-eye emissions "X"-rays. He also observed the action of these "X"-rays on photographic plates, and that these rays could traverse through the human body, showing the bones. In fact, the first "roentgenogram" was an image of his wife's hand. If you hover over Professor Roentgen's image, you will see an depiction of this historic image. This image marks the beginning of the science of Radiology.
Professor Wilhelm Konrad Roentgen received many awards, medals, and recognitions. In 1901 he was awarded the Physics Nobel Prize.
Sources:
1. http://www.nobelprize.org
2. "The origin of Medical Terms" Skinner, HA; 1970
Both original images (1) and (2) are in the public domain and courtesy of the National Library of Medicine.
Thanks to Megan Ohse for suggesting this article
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Sulcus/gyrus and brain, lateral view
These two different terms must be analyzed together. The Latin term [sulcus] means "groove or fissure". Its plural form is [sulci]. There are many anatomical sulci in the body, one of them being the costal sulcus in the ribs.
The second term [gyrus] is also Latin and means "circle or ring", as used in the words gyroscope or gyrations. In its adjective or descriptive form, [gyrus] is used to denote something "bent, curved, or broad-shouldered"1. The plural form is [gyri]. In the case of the brain a gyrus is formed as a mound or an elevation between the "valleys" of the sulci (see image). If you click on the image a secondary image depicting the lateral aspect of the brain will appear.
In the brain there are many sulci, the secondary image shows the lateral or Sylvian sulcus, and the central sulcus or sulcus of Rolando.
In relation to the central sulcus there are two gyri. The anteriorly situated precentral gyrus is considered the primary motor cortex and associated with voluntary motor activity (colored in green in the secondary image). The postcentral gyrus (colored in blue) is situated posterior to the central sulcus and is the primary sensory cortex, associated with somatic (bodily) conscious sensation.
Sources:
1. "The Origin of Medical Terms" Skinner, HA 1970 Hafner Publishing Co.
2. "Medical Meanings - A Glossary of Word Origins" Haubrich, WD. ACP Philadelphia
3 "Tratado de Anatomia Humana" Testut et Latarjet 8 Ed. 1931 Salvat Editores, Spain
4. "Anatomy of the Human Body" Henry Gray 1918. Philadelphia: Lea & Febiger
Initial image by:Albert Kok,courtesy of:Wikipedia.org. Second image modified from the original image by Henry Vandyke Carter, MD., courtesy of bartleby.com
Terms suggested by Sara Mueller.
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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.
Adam Christian Thebesius
Adam Christian Thebesius (1686- 1732). German physician and anatomist, Thebesius studied in the University of Leiden, Netherlands, where he received his doctorate in 1708 with the thesis "De circulo sanguinis in corde" (on the circulation of the blood in the heart). In 1713 he became a member of the Royal Academy of Natural Scientists (Kaiserliche Akademie der Naturforscher), where he adopted the Latin name "Eyryphon". Besides his natural sciences and medical research, Thebesius developed an interest in astrophysics.
Extremely interested in coronary circulation, Thebesius injected dyes and fluids in the coronary arteries, veins, and coronary sinus. Along with Raymond Vieussens (1635-1713) , Thebesius described all these structures. Today his name is attached to the eponymic Thebesian veins (venae cordi minima), and the Thebesian valve guarding the exit of the coronary sinus into the right atrium of the heart. Both these structures were mentioned in his 1708 doctoral thesis
Sources:
1. “The Role of the Thebesian Vessels in the Circulation of the Heart” Wearn, J.T. J Exp Med. 1928 January 31; 47(2): 293–315
2. The Story Behind the Word. Some Interesting Origins of Medical Terms. Wain,H. 1958.
3. The Origin of Medical Terms. Skinner, H.A. 1970
Original image in the public domain, courtesy of the National Library of Medicine
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The ventricular system of the brain is an interconnected system of cavities and ducts within the brain through which cerebrospinal fluid (CSF) circulates. The CSF is produced in the choroid plexuses located within the ventricles.
Ventricular system of the brain
Brain dissection - 4th ventricle
There are two large curved lateral ventricles, each found within a cerebral hemisphere. They connect with the third ventricle via an opening called the "foramen of Monro". The third ventricle connects with the fourth ventricle by way of a slender canal called the "cerebral aqueduct" or the "aqueduct of Sylvius".
The third ventricle is found deep within the brain between the right and left diencephalic portion of the cerebrum.
The fourth ventricle is located between the pons of the brain stem anteriorly and the cerebellum posteriorly. This ventricle has a rhomboidal shape and it connects with the external aspect of the brain and the subarachnoid space. Failure of this CSF drainage from the ventricles to the subarachnoid space can lead to pathological accumulation of CSF within the ventricles and hydrocephalus.
The line drawn image shows a lateral view of the brain with a superimposed image of the ventricular system. If you click on this image, you will see a superior view of a cast of the ventricular system (by Retzius).
The dissection image shows a posterior view of the brain stem and the cerebellum which has been opened in the median plane to expose the 4th ventricle. Click on the image to see a larger version.
Line images in the public domain by Henry VanDyke Carter, MD. (Gray's Anatomy) Dissection images property of CAA, Inc. Photographer E. Klein