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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 eponymic nodules (or nodes) of Arantius are thickenings of the tunica intima layer covering the ventricular aspect of the leaflets of the aortic valve, also known as the ventricularis layer (see blue arrows in the accompanying image). The thickening happens at the point of coaptation of all three leaflets. The shape and size of these growths varies from person to person and with age. The proper name for these structures is “nodes of the semilunar cusps” or “noduli valvularium semilunarium valvae aortae” in Latin
The portion of the leaflet proximal to the node of Arantius is the load-bearing portion and the portion of the leaflet distal to the node of Arantius is non-functional and is known as the “lunule”
Hypertrophy of the node of Arantius is not common, but when present and excessive it can lead to aortic valve dysfunction and insufficiency.
These excrescences of the valve leaflets are named after Giulio Cesare Aranzio (1530 – 1589), an Italian anatomist better known by his Latinized name Arantius.
Although most anatomists and surgeons use the same eponym for the excrescences of the pulmonary valve, those should be called the “nodes of Morgagni” after Giovanni Batista Morgagni (1682 - 1771) or "Noduli valvularum semilunarium valvae trunci pulmonalis" in Latin
Sources:
1. “The surface anatomy of the human aortic valve as revealed by scanning electron microscopy.” Hurle, JM et al Anat Embryol (Berl). 1985;172(1):61-7
2. “Hypertrophy of nodules of Arantius and aortic insufficiency: pathophysiology and repair.” Shapira, N et al Ann Thorac Surg. 1991 Jun;51(6):969-72
3. "The origin of Medical Terms" Skinner, AH, 1970
4. "Terminologia Anatomica: International Anatomical Terminology (FCAT)" Thieme, 1998
5. "Tratado de Anatomia Humana" Testut et Latarjet 8th Ed. 1931 Salvat Editores, Spain
Image property of: CAA.Inc.. Photographer: D.M. Klein
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The prefix [melan-] evolves from the Greek [μέλας] (m?las) meaning “black”. It can also be used as a root term and is found in many medical words as follows:
- Melanocyte: The suffix [ –(o)cyte] means cell. A black cell containing melanin, a black pigment
- Melanoma: The suffix [-oma] means “mass” or “tumor”. A black tumor, or a mass of melanocytes, as shown in the accompanying image.
- Melanomata: The suffix [-(o)mata] is the plural form of the suffix [-oma]. Multiple melanomas
- Melanin: Name given to the pigment that gives melanocytes its dark, black color
- Melancholy: It is also referred to as [melancholia]. The root term [-chol-] means “bile” and the word itself means “black bile”. In the old physiological theory of “the four humors” black bile represented a bodily fluid that in excess could lead to a dark, pensive frame of mind and eventually depression.
It is also found in the medical word [melena] referring to dark, blackened feces as a result of digested blood in the feces, pathognomonic of bleeding into the gastrointestinal tract. This word evolved from the early Latin (and later British English) spelling of this prefix as [melena], later eliminating the “a”, ending as [melen-]
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The prefixes [a-] and [an-] take their origin from the Greek [άνευ], meaning “without”, or “absence”.They are used in many medical terms:
- Analgesia: The root term [-alg-] means “pain”. Without pain
- Anesthesia: The root term [-thes-] means “sensation”. Without sensation
- Atrophy: The root term [-troph-] means “to grow”. Without growth
- Aplasia: The root term [-plas-] means “development”. Without development
- Aphasia: The root term [-phas-] means “speech”. Without speech. Do not confuse with dysphasia
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The root term [-troph-] arises from the Greek [τροφή] (trophi), meaning “food”, to feed”, or “growth”. The addition of the suffix [-y], meaning “process of” allows us to form the following medical terms:
- Hypertrophy: The prefix [hyper-] means “excessive”. Excessive growth
- Dystrophy: The prefix [dys-] means “abnormal”. Abnormal growth
- Eutrophy: The prefix [eu-] means “good” or “well”. Good growth, referring to normal growth
- Atrophy: The prefix [–a] means “absence” or “without”. Absence of growth
The addition of other suffixes such as [-ic] gives us descriptive or adjectival forms of the same root: Hypertrophic, dystrophic, eutrophic, and atrophic.
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The sinuses of Valsalva are dilations related to both the aortic root of the ascending aorta and the root of the pulmonary trunk. These sinuses form part of the functional aspect of the corresponding aortic valve and pulmonary valve. Each one of these semilunar valves presents normally with three sinuses of Valsalva, although the sinuses of the pulmonary valve are smaller than those of the aortic valve.
One of the problems encountered when describing each sinus of Valsalva is the fact that the sinus itself is not a structure, but a space. This space is found between the corresponding valve leaflet (or cusp) and the arterial wall which presents with a concavity, thus creating the sinus. This concavity is important functionally as it allows the leaflet to “flutter” in the arterial stream without getting stuck to the arterial wall. Physiological studies on the presence of the sinuses of Valsalva indicate that they play an important role decreasing of minimizing the stress of the valve leaflets.
The dilation of the sinuses of Valsalva also creates a bulbous region at the origin of both the ascending aorta and the pulmonary trunk, the “root” of these arteries. For a better view of this bulbous region, click here. The boundary between the bulbous sinusal segment and the tubular segment of the arteries is known as the sinotubular junction (STJ).
The accompanying image shows a human ascending aorta that has been cut open to show the sinuses of Valsalva (yellow arrows), and the three cusps (leaflets) of the aortic valve. These are the non-coronary cusp (NCC), right coronary cusp (RCC), and the left coronary cusp (LCC). The ostia of the coronary arteries are visible inferior to the STJ.
The sinuses of Valsalva are named after Antonio Maria Valsalva (1666 - 1723), an Italian physician and anatomist.
Sources:
1. “Anatomy of the aortic root: implications for valve sparing surgery” Charitos EI, Sieveres, HH Ann Cardiothorac Surg 2013;2(1):53-56
2. “Clinical Anatomy of the Aortic Root” Anderson, RH Heart 200; 84: 670–673
3. “The Anatomy of the Aortic Root” Loukas, E et al. Clin Anat 2014; 27:748-756
4: "Stress Analysis of the Aortic Valve With and Without the Sinuses of Valsalva" Beck, A et al J Heart Dis 2001; 10 (1) 1-11
Image property of: CAA.Inc.>. Photographer: D.M. Klein
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The word [sinus] is Latin and refers to a "pocket" or a "curved surface or structure". In medical terms the word [sinus] is used more in the meaning of "pocket" and refers to a cavity that has only one entrance (or exit) both in anatomy and surgery.
The term is used properly when referring to pocket-like structures such as the "sinuses of Valsalva" or the "prostatic sinus", as well as the sinuses found in the cranium such as the frontal sinus, the ethmoidal sinus, the sphenoid sinus, etc.
The word is incorrectly used to denote structures that have more than one entrance (or exit) such as the coronary sinus or the venous sinuses found in the cranial dura mater.
The corresponding root term is [-sin-] which then can be used in words such as [sinotubular junction]