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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
(1621-1675)

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.

Sources:

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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Proximal / Distal

UPDATED:The term [proximal], from the Latin [proximus] meaning "next" and its counterpart [distal], from the Latin [distans] meaning "distant", have been poorly defined and this causes misunderstanding in the proper use of these terms. This is particularly true in the medical industry.

The classical definition of [proximal] are "nearest, closer to the origin, closer to the point of reference" and also "closer to the beginning", or "opposite of distal". [Distal] is, of course, the opposite. All of these definitions are lacking a consensus between the participants in a conversation. This lack of proper definition could potentially lead to problems in an interventional situation and a patient could be injured.

In our lectures and training materials we use a working definition1 as follows:

Proximal has two meanings:

1- Closer to the point of attachment, where one end of the attached structure is free, and

2- Closer to the point of origin of flow of a fluid”

Distal is of course, opposite to proximal.

In the first acception of the word, a clear example is the attachment of the upper and lower extremities. Moving away from the shoulder or the hip joint is a distal movement. “The wrist joint is distal to the elbow joint”. The same is true for the Fallopian (uterine) tube, where the proximal attachment of the tube is to the uterus and the free distal end of the tube is its fimbriated end.

In the second acception of the word, in any anatomical structure, organ, or system where there is flow of a fluid (food, urine, bile, blood, etc.) it is accepted that normal flow (antegrade flow) goes from proximal to distal and that abnormal flow (retrograde flow) goes from distal to proximal.

1. Use of this definition is permitted, as long as CAA, Inc. is credited, or a link to this article is posted with it.
Image property of: CAA.Inc. Artist: Victoria G. Ratcliffe