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

Thomas Willis, MD
Thomas Willis

An English physician and anatomist, Willis was born on his parents' farm in Great Bedwyn, Wiltshire, where his father held the stewardship of the Manor. He was a kinsman of the Willys baronets of Fen Ditton, Cambridgeshire. He graduated M.A. from Christ Church, Oxford in 1642. In the Civil War years he was a royalist, and was dispossessed of the family farm at North Hinksey by Parliamentary forces. In the 1640's Willis was one of the royal physicians to Charles I of England. He obtained his medical degree in 1646.

Thomas Willis might well be one of the greatest physicians of the 17th century.He is one of the founders of the Royal Society of London. He is remembered by his many publications, especially "Cerebri Anatome: Cui accessit Nervorum Descriptio et Usu", where he describes the arterial anastomoses at the base of the brain. This work is also the first detailed description of the vasculature of the brain. Willis described nine cranial nerves.

He is considered as the father of Neurology as a discipline. He used the term "neurology" for the first time in 1664. He described several neurological conditions

The Arterial Circle of Willis is a famous eponymous structure found at the base of the brain. It represents an anastomotic roundabout that connects the right and left sides as well as the carotid and vertebral arterial territories that supply the brain. Named after Thomas Willis, this structure was known well before him, but it was Willis who described its function.  If you click on the image or here, you will be redirected to a detailed description of this structure.


1. "The legendary contributions of Thomas Willis (1621-1675): the arterial circle and beyond" Rengachary SS et al J Neurosurg. 2008 Oct;109(4):765-75
2. "Thomas Willis, a pioneer in translational research in anatomy (on the 350th anniversary of Cerebri anatome)" Arraez-AybarJournal of Anatomy, 03/2015, Volume 226, Issue 3
3. " The naming of the cranial nerves: A historical review" Davis, M Clinical Anatomy, 01/2014, Volume 27, Issue 1
4. "Observations on the history of the circle of Willis". Meyer A, Hieros, R.Med Hist 6:119–130, 1962

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This is a Greek compound word. [ana-] meaning "through or complete", the root term  [-stom-] from [stoma], meaning "mouth or opening" and the suffix [-osis] meaning "condition". Usually [-osis] refers to a disease, but in this case it refers to an action or process. The plural form for [anastomosis] is [anastomoses].

The word [anastomosis] then refers to the "process or action of creating a complete opening". In reality an anastomosis is the process of creating a permanent opening between two structures which allows for drainage or flow from one structure into the other. The suffix [-ostomy], being the term for "drainage" is the best suffix to describe an anastomosis. An anastomosis can be the result of a surgical procedure or found as a natural occurrence, such as the anastomoses found in the arterial circle of Willis or an abnormal fistula.

The accompanying image shows an early 1900's depiction of an anterior gastrojejunostomy. The term [gastrojejunostomy] is then the "creation of a drainage opening (a common mouth or opening) between the stomach and the jejunum, the second portion of the small intestine.

Anterior gastrojejunostomy (Babcock)

It is our belief and core competency, that surgical medical device sales representatives and managers should be completely familiar with this medical term, as well as the many types of anastomoses that can be performed surgically. To this end, we have developed a video on the History of Surgical Stapling. At the end of a video you can see a demonstration of the use of these devices to create an anastomosis