Medical Terminology Daily (MTD) is a blog sponsored by Clinical Anatomy Associates, Inc. as a service to the medical community, medical students, and the medical industry. We will post a workweek daily medical or surgical term, its 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.

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A Moment in History

Johann Gottfried Zinn

Johann Gottfried Zinn

Anatomist and botanist, Johann Gottfried Zinn was born on December 6, 1727 in the city of Ansbach, Germany. He started his medical studies in his native city, becoming later a student of Dr.  Albrecht von Hallers at the University of Göttingen, and received his MD in 1749.

He left for Berlin to continue his studies but came back shortly thereafter. He became a professor of anatomy at the University of Göttingen and in 1753 he also became the director of the botanical garden in the same city.

He is known for his anatomical treatise on the anatomy of the human eye: “Descriptio anatomica oculi humani iconibus illustrata”. Because of this, his name has become an eponym in the “Zonule of Zinn”, a ring of strands that forms a fibrous band connecting the ciliary body with the capsule of the lens of the eye. Zonule of Zinn is sometimes referred to as the suspensory ligaments of the lens, or the “ligament of Zinn”. His name is also attached to the anular ring tendon found in the posterior aspect of the eye, the "anular tendon of Zinn". This ring serves as attachment for all the extraocular muscles of the eye and the optic nerve passes through the center of the ring.

Carol Linné (Carolus Linneaus) named a genus of flowers in the family Asteraceae known vernacularly today as “Zinnia” in his honor. Hover your cursor over his portrait to see the flower.

The chapter on orbital anatomy of his anatomy book, taken from the second edition in 1780, has been translated and the first of three parts is published in an issue of “Strabismus”

His book "Catalogus Plantarum Horti Academici Et Agri" can be seen online here.

His life was short, dying at the early age of 32, but his name lives on in the name of a beautiful flower.

1. “Johann Gottfried Zinn" Simonz, HJ Strabismus – 2004, Vol. 12, No. 2, p. 125 
2. "Anatomical Description of the Human Eye" Zinn, JG Strabismus, 13:45–52, 2005 
Images: Public Domain by Wikipedia Commons. 1. Own work I_am Jin, and H. Wilhem Dietz

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Acute margin

The "acute margin" refers to the anteroinferior border of the heart. It is also known by its Latin name [margo acutus].

The name of this border or margin of the heart is quite descriptive. If you observe the angle formed between the anterior or sternocostal surface of the heart with the posterior or diaphragmatic surface of the heart, you can see that the angle between these two surfaces is less than 90 degrees, therefore an "acute" angle. The corresponding border between these two surfaces has to be called the "acute margin"!

In relation to the acute margin of the heart there is usually found one of the longest branches of the right coronary artery. This artery that runs alongside the acute margin, is the "acute marginal artery", In an angiogram, this artery clearly depicts the anteroinferior border of the heart.

Click on the image for a larger depiction. Here is a link to the article on the "obtuse margin" of the heart.

Acute margin of the heart. SVC= Superior vena cavaImage property of: CAA.Inc.Artist: Victoria G. Ratcliffe

Posterolateral artery

The posterolateral artery, also known as the "retroventricular artery" is one of the two terminal branches of the right coronary artery. The other terminal branch is the posterior interventricular artery or PDA. This artery presents with many variations, from being absent to extremely long arteries with extensive branching that take some of the territory of the circumflex artery. The posterolateral artery extends from the crux cordis to the left side of the heart in the atrioventricular sulcus.

The AV node artery, which provides blood supply to the AV node (a component of the conduction system of the heart) may arise from the posterolateral artery instead of arising from the right coronary artery or the posterior interventricular artery.

When present, the posterolateral artery provides some posterior left ventricular branches and maybe some posterior left atrial branches. See the accompanying image, you may click on the image for more information. The image depicts a posterolateral artery slightly longer than usual.

Posteroinferior view of the heart. IVC=inferior Vena CavaImage property of: CAA.Inc. Photography: Efrain Klein


Sir William Osler

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.To search all the articles in this series, click here.
Sir William Osler (1849-1919). William Osler was born in Bond Head, Canada, in what today is known as Ontario, of English parents. He started his college studies to become a minister, but realizing his true vocation was in medicine, he entered the Toronto School of Medicine, earning his medical degree in 1872.

Osler completed postgraduate studies in Europe, returning as a Professor at the McGill University. In 1884 he moved to Philadelphia to the University of Pennsylvania. In 1889 he left to become Physician-in-Chief and one of the founders of the newly-built John Hopkins hospital. His contributions to this new hospital and the American medical education are innumerable. Dr. Osler initiated the residency programs used today, as well as the programs of third and fourth year medical students in bedside patient rounds.

A prolific writer, Dr. Osler penned over 1,500 articles, monographs, and books, some of which are famous. His “Principles and Practice of Medicine” was published for a record 17 editions and 76 years (1892 -1968)! One of his most famous addresses is “Aequanimitas”, which he delivered when leaving the University of Pennsylvania.

Sir William Osler
Original image courtesy of "Images from the History of Medicine" at  www.nih.gov
In 1905 Dr. Osler accepted the position of Royal Chair of Medicine at Oxford, in England, and in 1911 he was awarded the title of “Sir William Osler”.

Personal Note: In June 1999, I had the opportunity to visit the collection of the John Martin Rare Book Room at the University of Iowa Medical School. I was allowed to read and handle original copies of the Fabrica and the Epitome by Vesalius as well as other original and rare medical books, including De Muto Cordis, by William Harvey. The books I had the opportunity to review were placed on an antique desk that belonged to Sir William Osler. A moment that has stayed with me, as it was the confluence of great individuals: Andreas Vesalius, the anatomist; William Harvey, the physiologist, and Sir William Osler, the medical educator. Dr. Miranda

“Sir William Osler, M.D., C.M.” Sarik, J. Yeo, Ch.Pinckney J. The American Surgeon78.4 (2012): 385-7.
“Sir William Osler and gastroenterology” Chaun H. Can J Gastroenterol (2010) 24:10 615-618
“Sir William Osler (1849-1919)” Haas, LF J Neurol Neurosurg Psychiatry 1999 67: 137
“Sir William Osler (1849-1919)”Christian, HA Proc Amer Acad Arts Sci (1922) 496-499


Of Latin origin, the word [coarctatio] means "to press together", or to confine. It is used as a synonym with "stricture" or "stenosis".

The term [coarctation] is used today used mostly to describe a narrowing, stricture, or stenosis of blood vessels, such as "coarctation of the aorta"


The pisiform bone is one of the four bones that comprise the proximal row of the carpus or carpal bones that form the wrist. It is the smallest of the carpal bones, is spheroidal in shape, and presents with only one articular surface (see image).

Its name originates from the Latin [pisum], meaning "pea". It is also known as "os pisiforme" or "lentiform bone", because some feel it is shaped like a lentil.

The pisiform bone articulates posteriorly with the triquetrum, and has on its anterior (volar) surface attachments to the transverse carpal ligament, and to the Abductor Digiti Quinti, and Flexor Carpi Ulnaris muscles.

The accompanying image shows the anterior (volar) surface of the wrist. Click on the image for a larger picture.

Scaphoid bone - anterior (volar) view of the wrist

Image modified from the original: "3D Human Anatomy: Regional Edition DVD-ROM." Courtesy of Primal Pictures


This is a Latin word meaning a trench, a ditch, or an excavation. It arises from the Latine term [fodere] meaning "to dig". The plural form for "fossa" is "fossae".

There are many fossae listed in human anatomy, here are some of them:

fossa scaphoides: found in the pinna
fossa ovalis: found in the wall of the right atrium
fossa triangularis: found in the pinna
ischioanal fossa: a triangular fossa found in the perineum, inferior to the pelvic diaphragm and superior to the urogenital diaphragm, etc.