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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 word [fovea] is Latin, and means a "small pit" or a "small depression", a small round fossa. There are two plural forms in use. The first is the Latin form [foveae] and the second one is the English form [foveas]. In human anatomy foveae are usually round in shape.
There are several foveae described in the human body. One of them is the fovea centralis of the eye, a small round depression in the retina characterized by the presence of a large number of cone cells and responsible for highest visual acuity.
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The [vertebral canal], also known as the spinal canal, is formed by the juxtaposition of consecutive vertebrae, and their vertebral foramina. It is a long canal that extends from the superior border of C1 (Atlas), and ends at the sacrococcygeal junction. Some anatomists consider the superior boundary of the spinal canal to be at the lower border of the foramen magnum of the occipital bone.
The vertebral canal is bound anteriorly by the vertebral bodies (corpora), the intervertebral discs, and the anterior longitudinal ligament. Posteriorly it is bound by the vertebral laminae, which meet in the midline at the base of the spinous process, and the ligament flava. The lateral boundary of the vertebral canal are the vertebral pedicles and the intervertebral foramina.
The vertebral canal contains the spinal cord with its meninges, spinal arteries and venous plexuses, and epidural fat.
Image property of: CAA.Inc. Photographer:David M. Klein
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The prefix [hypo-] is a derivate from the Greek [υπό] (ipo) which means "under", "deficient" or "below". Its uses include:
- Hypoglycemia: The root term [-glyc] means "sugar" and the suffix [-emia] means "blood". Low blood sugar
- Hypoplasia: The root term [-plasia] means "to develop". Under development
- Hypochondriac: The<root term [-chondr-] means "cartilage". Below the cartilage. A detailed explanation of this word will follow soon
- Hypodermic: The root term [-derm] means "skin". Below the skin
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The prefix [hyper-] is a derivate from the Greek [υπερ] which means "over" or "above". In today's medical terminology, it is used to mean "in excess of". Its uses include:
- Hyperglycemia: The root term [-glyc] means "sugar" and the suffix [-emia] means "blood". Excess blood sugar
- Hyperplasia: The root term [-plasia] means "to develop". Excess development
- Hyperactivity: Excess activity
- Hyperesthesia: The root term [-esthesia] means "sensation". Excessive sensation
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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.
Jacobus Sylvius
Jacobus Sylvius (1478 - 1555). French physician, teacher, and anatomist, Sylvius was born in poverty as Jacques Dubois, in the city of Louisville, near Amiens. He would eventually become known as Jacobus Sylvius Ambianus. In spite of his humble beginnings Sylvius entered the College of Tournay. Too poor to continue his studies he started to instruct in anatomy, which helped him earn enough to obtain a bachelor’s degree in Medicine in 1531 in Montpellier.
Sylvius returned to Paris as a demonstrator in anatomy, where he excelled. He had many famous students, among them was Andrea Vesalius. Sylvius followed strictly the teachings of Galen, a situation that eventually caused not only his downfall, but enmity with Vesalius and others. Sylvius was also of the opinion that the student of anatomy should learn from dissection as well as from the books. One of Sylvius’ most important achievement was that he added to the Galenic numerical description by numbers, a descriptive nomenclature creating many names in used today such as brachialis, tibial, peroneus, scalene, serratus, biceps, triceps, etc. He is also responsible for many other names such as femoral, popliteal, subclavian, phrenic, axillary, spermatic, epiploic, etc.
Sylvius was a controversial man. He was known for being greedy, a miser, and the use of foul language, but at the same time he wrote a book to guide the poor student who wanted to get through Medical School. He was finally appointed professor of Medicine at the Royal College of Paris, a position he held until his death in 1555.
Sylvius was so enraged with Vesalius’ denouncement of Galen as being wrong, that he started a personal war against him including sending letters to the King and through public letters where he called Vesalius a madman (vaesanus), plus “purveyor of filth and sewage, pimp, liar, and various epithets unprintable even in our own permissive era” (excerpt from Magner, 1992)
Although many attribute the eponyms of the lateral cerebral sulcus (Sylvian fissure) and the cerebral aqueduct (aqueduct of Sylvius) to Jacobus Sylvius, these two structures are actually named after Franciscus Sylvius (1614 – 1672) a German anatomist. On top of this, some of the structures actually discovered by Jacobus Sylvius were named eponymically after someone else, like the incomplete valve found at the junction of the inferior vena cava and the right atrium, named after Bartholomew Eustachius (c.1520 - 1574).
Sylvius’ contribution to anatomy is immeasurable, but his personality traits have made him lose status and almost forgotten.
Sources:
1. “Advice for Poor Medical Students: Sylvius, J. Translated by O’Malley CD J Hist Med 1962 17:141-151
2. “A Historical Lesson from Franciscus Sylvius and Jacobus Sylvius” Bakkum DC (2011) J Chir Hum 18:94-98
3. “A Historical Mistake: The aqueduct of Sylvius” Leite Dos Santos, AR et al Neurosurg Rev (2004) 27: 224-225
4. “Jacobus Sylvius (Jacques Dubois) 1478-1555 – Preceptor of Vesalius” JAMA (1966) 195 13; 1147
5. "Andreas Vesalius; The Making, the Madman, and the Myth" Joffe, Stephen N. Persona Publishing 2009
6. “A History of Medicine” Magner, LN Ed. M Deckker Pub 199
Original image courtesy of Images from the History of Medicine
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The [vertebral laminae] are two bilateral thin, flat regions of the posterior components of a vertebra. Along with the pedicles and the vertebral body (corpus) they are part of the boundaries of the vertebral foramen.
The laminae have regional variations. In the cervical region they are small and more rounded; in the thoracic region they are larger, and overlap each other. In the lumbar region in spite of being relatively large, they do leave intervertebral spaces that allow a physician to perform a "spinal tap" by passing through the ligamentum flavum into the subdural space to take a sample of cerebrospinal fluid.
Image property of: CAA.Inc.Photographer: David M. Klein