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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The jejunum is an intraperitoneal organ, it is the second portion of the small intestine and part of the digestive tract. It begins at the duodenojejunal junction  where it is related to the ligament of Treitz, and extends 8 to 9 feet, continuing distally with the ileum.

Being intraperitoneal, it is anchored to the posterior abdominal wall by the double-layered mesentery through which the jejunum receives its blood and nerve supply. At the root (base) of the mesentery are the superior mesenteric vessels.

The Latin word [jejunis] means "empty" or "fasting". The Latin term [jejunum] was used by the Romans to denote the first meal of the day, breakfast, when you have an "empty" stomach. The term was associated with this segment of the small intestine, as it is most of the time found empty in cadavers being dissected.

There is no clear anatomical boundary between the jejunum and ileum, as they blend smoothly one into the other. There are several gross changes from jejunum to ileum, one of them being that the complexity of the mesenteric arterial arches increases from proximal to dista. See the accompanying image. Click on it for a larger depiction.

Jejunoileal vascular supply (www.bartleby.com)

Two interesting side notes: In English, the term for the first meal of the day is self-explanatory: [break - fast], adding to the Roman concept of "fasting" or "jejunum". In Spanish, the term for breakfast is [desayuno], where the word [ayuno] means "fasting", therefore the word [des-ayuno] also means "the end of fasting". Look at the evolution (in Spanish) from [jejunum] to [yeyuno] (the Spanish term for the organ) to [ayuno], meaning "fasting" or "empty".

1. "Clinically Oriented Anatomy" Moore, KL. 3r Ed. Williams & Wilkins 1992
2. "The origin of Medical Terms" Skinner, AH, 1970
Images and links courtesy of Bartleby.com