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

Crus / crura

The word [crus] is Latin (cruris) and refers to the leg, or region of the shin. It is commonly used to mean "leg" or "pillar". The plural form is [crura].

Several authors suggest a relation of [crus] with another Latin term [crux] meaning "cross" as if a cross is formed by two [crura] (legs).

The term crus is widely used in human anatomy:

- crus cerebri: there are two crus cerebri in the anterior aspect of the mesencephalon
- crura of the penis: the posterior aspect of the corpora cavernosa firmly attached to the ischiopubic rami
- crura of the clitoris:  the posterior aspect of the corpora cavernosa firmly attached to the ischiopubic rami
- crura fornix cerebrii: the posterior converging bands that form the fornix of the cerebrum

Special mention is deserved by the crura of the diaphragm. There are two pairs of diaphragmatic crura. The esophageal crura (right and left) which bound the passageway of the esophagus from the thorax into the abdomen, the esophageal hiatus. The esophageal crura have a muscular structure. The aortic crura (righ and left) allow for passage of the aorta into the abdomen, and although muscular superiorly, they are mostly tendinous. The accompanying image shows an anteroinferior view of the respiratory diaphragm. Click on the image for a larger picture.

Respiratory diaphragm - anteroinferior view (modified from bartleby.com) 1. Right tendinous aortic crus 2. Left tendinous aortic crus IVC=Inferior Vena Cava

1. Right tendinous aortic crus 2. Left tendinous aortic crus IVC= Inferior vena cava. Modified from the original image. Courtesy of www.Bartleby.com

Luigi A. Galvani

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.

Luigi A. Galvani (1737-1798). Italian anatomist, surgeon, and physiologist, Luigi Aloisio Galvani was born in Bologna in 1737. Although he started his studies to join the church, Galvani followed with medical studies at the University of Bologna, where he became a skilled anatomist and surgeon. On July 15, 1759 Galvani obtained his degree in medicine and philosophy.

He was interested in the effects of electricity on tissues and through observation and experimentation he postulated the existence of "animal electricity", that is, electricity generated within the tissues. He postulated the possibility that nerves carried electricity. His theories led to a passionate controversy with Volta, who denied Galvani's postulates. Galvani's theories would only be confirmed after his death. 

Galvani was deeply religious, and when forced by government officials to take an oath of atheism, he refused. He was stripped of his position and was lead to poverty. His position was restored close to his death. In his honor, Andre Ampere (1775-1836) named one of his inventions that measures electricity,  the "galvanometer". His name is also present in vernacular English, when we say that a rock star or a movie "galvanizes" an audience, meaning it was "electrifying"!

1. "Luigi Galvani" Haas LF J Neurol Neurosurg Psychiatry v.56(10); Oct 1993
2. "Luigi Galvani and the foundations of electrophysiology" Cajavilca C, Varonb,J,Sternbachc GL; Resuscitation 80 (2009) 159–162

Luigi Galvani

Original imagecourtesy of National Institutes of Health.


The capitate bone is one of the four bones that comprise the distal row of the carpus or carpal bones that form the wrist. It is the largest of the carpal bones and is placed in the center of the wrist (see image).

Its name originates from the Latin [caput], meaning "head". The capitate bone presents a large, rounded area, called the "head". To complete the homology, the capitate bone also has a narrow segment called the "neck", the rest of the bone called the "body". It is also known as "os capitatum" or "os magnum"

The capitate bone articulates with seven bones, including the scaphoid, lunate, trapezoid, hamate, and the three central metacarpals (2nd, 3rd, and 4th).

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


The duodenum is a mostly retroperitoneal organ, part of the digestive tract, and the most proximal portion of the small intestine. This organ is approximately 10 inches in length (24.5 cm). It starts at the pylorus of the stomach, has a "C" shape, curving around the head and the neck of the pancreas, to end at the duodenojejunal junction.

The duodenum is described as having four segments of differing length, usually named numerically:

- First segment: about two inches in length, it is dilated and called the "duodenal ampulla", or "superior duodenum"
- Second segment: about three inches in length, it receives bile and pancreatic juice through the hepatopancreatic ducts and ampullae. It is also called the "descending duodenum"
- Third segment: about four inches in length, it crosses the midline, and is also known as the "horizontal" or "transverse duodenum"
- Fourth segment: one inch in length, this is the shortest segment, it ascends towards the duodenojejunal junction, which is tethered to the diaphragm by a fold of peritoneum around a fibromuscular band called the "ligament of Treitz". At this point the retroperitoneal duodenum becomes the intraperitoneal jejunum. This fourth segment is also called the "ascending duodenum"

Retroperitoneal organsImage property of:CAA.Inc.Artist:Dr. E. Miranda
The name of the organ is interesting. Most textbooks claim that is originates from the Latin [duodeni], meaning "twelve". The fact is that the duodenum was originally named in Greek [δώδεκα δάχτυλαν] meaning "twelve fingers". If you place both your hands together and add 1/4 of an inch to each side (as if you had an extra finger on each hand) that measures approximately 10 inches. The term was shortened by an incorrect translation to "twelve" by Gerard of Cremona (1114 - 1187) who called it "duodenum", a bad translation, as twelve fingers in Latin is [duodecim digitorum].

"Clinically Oriented Anatomy" Moore, KL. 3r Ed. Williams & Wilkins 1992
2. "The origin of Medical Terms" Skinner, AH, 1970 


This prefix is derived from the Greek and means "slow". Most everybody knows about [bradycardia] meaning "slow heart", but there is a large number of applications of this prefix as follows:

• Bradytrophia: from the Greek [trophe] meaning "to feed" or "nutrition". Braditrophia is a slow nutritional process
• Bradypnea: from the Greek [pnoia], meaning "breath" or "air". Bradypnea is an abnormally slow breathing rhythm
• Bradylalia: from the Greel [lalein] meaning "to talk". Bradylalia is a slow articulation or formation of words, sometimes also known as [bradyarthria] or [bradyphasia]. See the article on aphasia and dysphasia here
Bradykinesia: from the Greek [kinesis], meaning "movement". Bradykinesia means "slow movement", also known as [bradypragia]
• Bradycrotic: from the Greek [krotos], meaning "pulse" "or pulsation" A bradycrotic agent slows down the patient's pulse or heart rate.
Bradytocia: from the Greek [tokos], meaning "birth". Bradytocia is a slow birthing process