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.
You are welcome to submit questions and suggestions using our "Contact Us" form. The information on this blog follows the terms on our "Privacy and Security Statement" and cannot be construed as medical guidance or instructions for treatment.
We have 1639 guests online
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.
"Clinical Anatomy Associates, Inc., and the contributors of "Medical Terminology Daily" wish to thank all individuals who donate their bodies and tissues for the advancement of education and research”.
Click here for more information
- Details
Click for a larger image
UPDATED: Root term meaning Thorax (Greek: [θώρακα] Chest plate or area covered by a chest plate). The thorax contains three areas, or regions, sometimes described as "spaces" (sic). These are two laterally situated pleural cavities, each containing a lung, and a median mediastinum, a large region containing the pericardium, heart, great vessels, thoracic duct, azygos venous system, esophagus, aorta, thymus, etc. The plural form for thorax is [thoraces].
• Thoracotomy: Opening of the thorax. Note that the term "thoratomy" en vogue nowadays is a misuse of the term
• Thoracocentesis: The suffix [-(o)centesis) means needle aspiration. Needle aspiration of the thorax
• Thoracoscopy: Visualization of the thorax
Personal note: There is a tendency, a trend to use the word [thorascopy] instead of the correct form [thoracoscopy]. The use of [thorascopy] is incorrect and should not be allowed in the clinical arena. In fact, it is not recognized by my medical spellchecker! Dr. Miranda
- Details
This suffix originates from two Greek root terms [ectos], meaning "out or outside" and "[tomos], which means "to cut" or "to open". The final [-y] means "process". The suffix [-ectomy] means "process of cutting out". Other synonyms are: extirpation, excision, and removal.
Applications of this suffix include:
- Pneumonectomy: Removal of a lung
- Gastrectomy: Extirpation of the stomach
- Nephrectomy: Excision of a kidney
- Cholecystectomy: Extirpation of the gallbladder
- Details
UPDATED: Latin word meaning "tail". The plural form is "caudae". The adjective use "caudal" or "caudad" means "towards the tail" or "inferior". Although not correct, in many anatomy books the term "caudal" is defined as "towards the feet", meaning that has become accepted through use. In reality this is a embryological term that can also be used in quadrupeds. The use of this term in the adult human is not correct, or at least should be avoided; unless you are truly going "towards the tail" i.e. coccyx
Applications of this word include:
- Cauda equina (the horse's tail): A structure formed by the inferior portion of the spinal cords and the corresponding ventral and dorsal roots, resembling a horse's tail.
- Caudate nucleus: One of the deep ganglia of the brain which has an elongated, curved extension resembling a tail
- Caudate lobe (of the liver): A small lobe of the liver that has a small projection resembling a tail, the caudate process.
- Details
Cauda equina dissection
The term cauda equina is Latin. The word [cauda] means "tail", and the word [equina] means "horse". The horse's tail.
Since the spinal cord is shorter that the spinal canal, there is a discrepancy as to the origin of the dorsal and ventral roots and their corresponding intervertebral foramen, where they exit as a spinal nerve. The cauda equina is found inside the sacrolumbar portion of the spine's dural or thecal sac, inferior to the conus medullaris, and is formed by the filum terminale and the dorsal and ventral roots found inferior to the distal end of the canus medullaris.
If you click on the accompanying image you will see a larger version. Observe the resemblance of the grouping of these roots to a horse's tail. For an image from Gray's anatomy click here.
Image property of CAA.Inc. Photographer:D.M. Klein.
Link and linked image courtesy of Bartleby.com
- Details
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.
Antoine Louis
Antoine Louis (1723- 1792). French surgeon, anatomist, and physiologist. Following his medical studies and a long career as a physiologist, Antoine Louis was named Permanent Secretary of the Royal French Academy of Surgery. His other titles were those of Professor of the Royal Academy, Consultant Surgeon of the Armies of the King, member of the Royal Society of Sciences of Montpellier, Inspector of the Royal Military Hospitals, and Doctor in Law of the University of Paris. As a member of these academies Louis was instrumental in the design and construction of the guillotine. Initially called the "Louisette", this device was later named after another French physician in the same committee, Dr. Joseph-Ignace Guillotin.
Antoine Louis' name is better know to history as the eponymic origin of the "sternal angle" also know as the "Angle of Louis" and synonymously (probably by misspelling or translation) the "angle of Lewis", and "angle of Ludwig". This anatomical landmark is extremely important as it serves as a superficial landmark for important anatomical occurrences (click here).
As a point of controversy, there are some that contest the history of this eponym adjudicating it to Pierre Charles Alexander Louis (1787-1872), another French physician dedicated to the study of tuberculosis.
Sources:
1. Srickland, N; Strickland A Angle of Louis, More Than Meets the Eye. MedTalks:
2. Ramana, R. K., Sanagala, T. and Lichtenberg, R. (2006), A New Angle on the Angle of Louis. Congestive Heart Failure, 12: 197–199
3. "The origin of Medical Terms" Skinner, HA; 1970
- Details
Click for an animation of the
sella turcica
UPDATED: The words [sella turcica] are Latin and mean "Turkish chair". The sella turcica is a depression found in the superior aspect of the sphenoid bone and it does resemble one! The accompanying image is that of a Turkish chair made in wicker. (wickerbydesign.com). The Turkish chair resembles a horse saddle with high ends.
If you click on the image, you will see an animation of the sphenoid bone highlighting the sella turcica, where you will see the resemblance between the chair and the bone.
The hypophysis or pituitary gland, which dangles from the hypothalamus by a neural stalk, is found within the concavity of the sella turcica, surrounded by the optic tracts laterally and by the optic chiasm anteriorly.
The depression of the sella turcica is sometimes called the [pituitary fossa] or [fossa hypophyseos]. It is bound anteriorly and posteriorly by four bony processes, the (left and right) middle and posterior clinoid processes.
The pituitary fossa is closed by a tent-like structure made of dura mater which has a small opening that allows the hypophyseal stalk to pass trough. This is the diaphragma sellae.
Question: Do you know that there are four named diaphragms in the human body? See if you can name them!
Image of the Turkish chair courtesy of wickerbydesign.com.Secondary animated image byBodyParts3D, courtesy of Wikipedia.