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 word [vermis] is Latin and means "worm". 

The vermis is the name given by Galen of Pergamon (129AD - 200AD) to the median lobe of the cerebellum, since when seen from the superior aspect, this cerebellar lobe looks like a multisegmented worm. See accompanying image, or click for a larger depiction. 

When seen in a median section, the cerebellar vermis looks like a multilobulated leaf with the fourth ventricle of the brain at its base. It is composed of several smaller lobules: Lingula, central, culmen, clivus, tuber vermis, pyramid, uvula, and nodular lobes.

Median section image link courtesy of UCLA Radiology

Superior view of the cerebellum (modified from bartleby.com)Modified from the original image. Courtesy of www.Bartleby.com

Anatomical variations (3)

"The Chirurgeon must knowe the Anatomie". Thus states Thomas Vicary (1460 -1561) on the knowledge of Anatomy. He continues: "...for all authors write against those surgeons who work in a man's body not knowing the Anatomie"1. There is no doubt that knowledge must include the awareness of the possibility of anatomical variations.  Some anatomical variations, like the "Corona Mortis" can be critical, and in some surgical cases, be the cause for exsanguination!

It is interesting that several medical schools are reducing the total number of hours working on, or moving away from cadaver disection in first year medical school and using computer simulations instead. No computer simulation will give the medical student the detail, variations, and feel of the tissues as actual hands-on experience. I am sure no one wants a surgeon whose first view of the internal aspect of a human body is a living patient...on the surgical table. 

It is a fact that "Nothing in the human body is really colored... or labeled" or as someone else said "nothing looks exactly like the anatomy book", unless it is photography, and then each photo is taken after hours of laboring to "Netterize" the organ or area that one is trying to detail. Nothing gives the future professional the exact idea of what to expect in the future patient than the hours and hours of laborious work in the anatomy laboratory.

Coronary artery arising from the pulmonary trunk (Brooks, 1886)
The same is true with anatomical variations, one "standard" digital cadaver,even with built-in anatomical variations does not give the student the sense of awe and discovery when an anatomical variation is found, interpreted, and analyzed with a group of peers, contributing to the learning process and the formation of future health care professionals.When questioning what is normal or abnormal, Dr. Elizabeth Murray says it most elegantly: "The cadaver is always right"

The image depicts a case of a coronary artery arising from the pulmonary trunk

1. "The Chirurgeon must knowe the Anatomie" R. Shane Tubbs Clin Anat 26:417 (2013)
2. "Two cases of an abnormal coronary artery of the heart arising from the pulmonary artery"Brooks, H; J. Anat. Physiol. 20:26-29, 1886 (anatomyatlases.org)



Anatomical variations (2)

"No anatomical structure has the moral obligation to be where they are supposed to be"

Not only may an anatomical structure be absent, such as in the case of renal aplasia or agenesis, or in the case of a non-existent circumflex coronary artery, but sometimes extra structures can be found. Such is the case where a kidney can present two or even three ureters, all functional. Double inferior vena cavae, cervical ribs, lumbar ribs, the list goes on and on!

Muscles can be added to this list, again, with absence of a muscle, or with new and completely unexpected attachments. An example of this is the presence of a continuation of the rectus abdominis muscle into the chest region, a variation called a sternalis muscle.

The accompanying image shows the sternalis muscle in one of the "muscle plates" of De Humani Corporis Fabrica Libri Septem, published in 1543 by Andreas Vesalius. This image was criticized by showing a muscle that does not exist, although Vesalius clearly stated in the text of his book that this was an anatomical variation that he had seen.

For many decades surgeons had to operate and "see what they could find". There were the days of the exploratory laparotomy. After the discovery of the application of X-rays by Wilhem Konrad Roentgen (1845 - 1923) and the incredible advances in imaging techniques including CT-scan, MRI, PET, etc, the surgeon is now not usually surprised by anatomical variations.

Sternalis muscle (Andreas Vesalius 1543)
There are areas in the body that have an high rate of anatomical variation, such as the hepatobiliary region, which includes the "Triangle of Calot". In this area, the standard anatomy is found only in 64% of the cases! In the rest, expect the unexpected. Lahey (1948) states "...the fact that cholecystectomy is a dangerous operation. It is dangerous unless one realizes.... that anomalous anatomy is very common". Today the dangers are less, because of better visualization and technology, but anatomical variations are still there.

Another area where anatomical variations are extremely important is the heart's coronary circulation. Anatomical variations can cause different cardiac dominance. Normal anatomy states that there are two coronary arteries, yet, up to five separate coronary arteries arising directly from the ascending aorta have been described! There is one variation where the left coronary arises from the right coronary artery, effectively having only one artery arise from the aorta and being in charge of all the arterial supply to the heart. What happens if this single artery stenoses? Bear in mind that this is not an "anomalous" vessel, it is just an anatomical variation.

1. Lahey DH, discussing the paper "Partial Hepatectomy with Intrahepatic Cholangiojejunostomy" by Wilson H, and Gillespie CE, Ann Surg. 1949 June; 129(6): 756–765
2. "Renal aplasia is the predominant cause of congenital solitary kidneys" Hiraoka, M et al Kidney Int. 2002 May;61(5):1840-4.

This article is the second in a series of three; Click here for the first article

Anatomical variations (1)

"The only constant in anatomy is variation". This dictum is incredibly powerful and true. Even the so-called "anatomical constants" are subject to it.

One common misconception is that "we are all the same". This could not be further from the truth. Every body is different from every else's body. Anatomical variations range from the minimal to the incredible. One of the most interesting anatomical variations is the one called "situs inversus". In this case the individual is a mirror image of a human. The apex of the heart points to the right side of the body; the duodenum circles to the right, the liver "hangs" from the left side of the respiratory diaphragm, etc. This particular anatomical variation presents in different degrees and can sometimes coexist with some cardiovascular congenital abnormalities.

Third supernumerary kidney. (modified from Dixon, 1911
Of course there are minor anatomical variations that have no effect on daily life at all and are only discovered by accident, or upon autopsy or dissection. One of the most complete resources on this topic is the Illustrated Encyclopedia of Human Anatomic Variations. An excerpt from this site states: "It is clear that textbook writers and teachers over the centuries, even until today, fail to understand or to transmit to their students the crucial concept that anatomical and physiological diversity and variation is a canon of living organisms. This failure leads to the belief that textbooks are conveying immutable facts with only few anomalous exceptions".

Shown here is an extremely rare case of a third kidney. Dixon (1911) describes in his research paper that as of that date, only 10 cases were known, of these only eight were recorded, with 87% of them found on the left side of the body. Click on the image for a larger depiction.

Source and primary image: "Supernumerary kidney: The occurrence of three kidneys in an adult male subject" Dixon, A.F. J. Anat. Physiol. 45:117-121, 1911.



The prefix [para-] has a Greek origin and means "beside" or "alongside". Today we add the meaning of "parallel to".

We see the daily application of this prefix  in words such as [paramedic], [parajournalism], [paralogism], and [paranormal].

Medical applications of the term include:

paraesternal: alongside the sternum, such as the internal thoracic vessels
paramedian: alongside the median plane
parasagittal: parallel to a sagittal plane (synomym with paramedian)
paraumbilical: alongside the umbilicus, such as paraumbilical visceral extrusion in a gastroschisis
parathyroid glands: glans that are found besides the thyroid gland, etc.

Otto C. Brantigan, MD

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.

Otto C. Brantigan, MD. (1904-1981) An American surgeon and anatomist, Otto Charles Brantigan  was born in Chattanooga, TN in 1904. Having dropped out of high school to help his family and working as a first class machinist, he decided to continue with graduate school. He studied at the Northwestern University in Chicago, where he graduated from the Medical School in 1933.  In 1948 he became Chief of Surgery, and eventually became Professor of Surgery, Professor of Thoracic Surgery, and Professor of Anatomy at the Maryland School of Medicine.  He retired in 1976 having earned many accolades for his profuse surgical work and publications.

As a surgeon of the times, Dr. Brantigan had a wide area of interest. His over 110 publications and surgical work range from thoracoscopy to vascular, plastic, cardiac, and orthopedic surgery. He is most remembered for the pioneer work he did on chronic obstructive pulmonary disease (COPD), emphysema and lung volume reduction surgery (LVRS), which he presented in 1958. The procedure had (at the time) a very high mortality rate  (16 -20%) and Brantigan's work was not readily accepted.

Dr. Otto C. Brantigan
It was not until J. Cooper and his team, revisited the operation proposed by Brantigan  that the operation was accepted, now with new surgical stapling and staple line buttressing technology.  Dr. Brantigan's name was recognized as a pioneer in lung emphysema surgery, unfortunately 14 years after his death. In 1994 his son, Dr Charles O. Brantigan delivered a beautiful biography of Dr. Otto Brantigan in the same meeting where Cooper presented his results with LVRS.

1. "Biography of Otto C Brantigan" C.O. Brantigan 1994 Meeting of the American Association for Thoracic Surgery
2. "LVRS in chronic obstructive pulmonary disease" Davies, L; Calverley, P. Thorax 1996;51(Suppl 2):S29-S34
3. ""Bilateral pneumectomy (volume reduction) for chronic obstructive pulmonary disease" Cooper, J.,The Journal of Thoracic and Cardiovascular Surgery Volume 109, Number 1:106-119
4. "The Surgical Approach to Pulmonary Emphysema" Brantigan, OC; Kress, MB; Mueller, EA. Chest. 1961; 39(5):485-499
5. "History of Emphysema Surgery" Naef, AP. Ann Thorac Surg 1997;64:1506-1508

Original image  courtesy of National Institutes of Health. Biography of Dr. Otto Brantigan courtesy of Dr. Charles O. Brantigan.