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 suffix [-oma] means "tumor", "mass", or "growth". It should be noted that the word [tumor] is originally Latin, and means "swelling" or "bulging". Sometimes the plural form [-omata] can be used.

It is a general misconception that the suffix [-oma] or the term [tumor] are synonymous with "cancer". This is not so. [Tumor] only means a mass and the type of mass, benign or malignant is not implied in the term. A cancerous mass will be denoted by the addition of the root term [-carcin-] meaning "cancer" therefore the combined root and suffix will be [-carcinoma]. There are other root-suffix combinations that also mean "cancerous".

The suffix [-oma] can be found in many medical words, such as:

Hematoma: from the Greek root [-hem-] meaning "blood". A mass of blood
Myoma:  from the root [-my-] meaning "muscle". A mass, growth, or tumor of muscle.
Fibroma: from the root [-fibr-] meaning "fiber". A mass of fibers. 
Fibromyoma: the combining form of "muscle" is [myo-], therefore "a mass of fibers and muscle" (Pl. fibromyomata)
Adenoma: from the Greek [aden-] meaning "gland". A mass that has a glandular look to it or a mass in a gland 

1. "The Language of Medicine" John H. Dirckx Pub: Harper & Row 1976
2. "Medical Meanings" Haubrich, William S. Am Coll Phys Philadelphia 1997
3. "The origin of Medical Terms" Skinner, AH, 1970

Giovanni Battista Morgagni

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.

Giovanni Battista Morgagni (1682 - 1771). Italian anatomist, physician, and pathologist, Morgagni was born in the city of Forli. He started his medical studies at the University of Bologna, graduating in 1701 with a degree in Medicine and Philosophy. In 1712 he became a professor of anatomy at the University of Padua, Italy, 175 years after Andreas Vesalius. Morgagni was offered and accepted the Chair of Anatomy in 1715 at the University of Padua. Although Morgagni held a position at the anatomy department of the University of Padua, his name is associated mostly with his pathological studies.

Morgagni was interested in the works of Theophile Boneti (1620 - 1689), who started analyzing the correlation between post-mortem anatomical findings and diseases. He tried to establish a relation between the disease and the cause of death. In 1761 Morgagni published his most influential work "De Sedibus et Causis Morburum Per Anatomen Indagatis"  (On the Sites and Causes of Diseases, Investigated by Dissection). His work was essential for pathological anatomy to be recognized as a science in itself.

Giovanni Batista Morgagni
Morgagni was elected to become a member of several Academies of Science and Surgery: The Royal Society of London, The Academy of Science in Paris, The Berlin Academy of Science, and the Imperial Academy of Saint Petersburg in Russia. He is remembered today by several eponyms in anatomy and pathology:

• Morgagni's caruncle or lobe, referring to the miidle lobe of the prostate
• Morgagni's columns: the anal (or anorectal) colums
• Morgagni's concha, referring to the superior nasal concha
• Morgagni's foramina: two hiatuses in the respiratory diaphragm allowing for passage of the superior epigastric vessels
 Morgagni's hernia: an hiatal hernia through Morgagni's foramen, in the respiratory diaphragm
• Morgagni's ventricle: an internal pouch or dilation between the true and false vocal cords in the larynx
• Morgagni's nodules: the nodules at the point of coaptation of the leaflets (cusps) of the pulmonary valve. Erroneously called the "nodules of Arantius", which are only found in the aortic valve

1. "A Note From History:The First Printed Case Reports of Cancer" Hadju, S.I. Cancer 2010;116:2493–8
2. "Giovanni Battista Morgagni" Klotz, O. Can Med Assoc J 1932 27:3 298-303
3. "Morgagni (1682 -1771)" JAMA 1964 187:12 948-950
Original imagecourtesy of National Institutes of Health.


The term [lumen] is Latin and means "light". It is an international measure of light intensity. The plural form is either [lumens] or the Latin version [lumina].

The question is how did this term end up meaning the "internal opening or cavity of a hollow organ"? Dr. J. Dirckx (1976) explains that the term [lumen] in gastrointestinal anatomy was not used until the late 19th century, but it was initially used by microscopists looking at cross sections of small vessels. Since the empty interior of the vessel was represented on the histological slide as a clear, lighted region, they started calling that the "light" of the vessel, or [lumen].

The root term for [lumen] is [-lumin-] and can be found in over 30 words in English and related to light, such as luminosity, luminaria, luminescent, luminous, illumination,  illuminator, intraluminal, transluminal, endoluminal, etc.

The correct adjective form for [lumen] is [luminal], as stated by Haubrich (1997). The point is that the use of the term "lumenal" as an adjective form for lumen is not correct. This term can be seen in many textbooks today. The proper form for the NOTES acronym should be "Natural Orifice Transluminal Endoscopic Surgery" and not "translumenal". 

See how you can "illuminate" this article by hovering your cursor over the light bulb!

1. "The Language of Medicine" John H. Dirckx Pub: Harper & Row 1976
2. "Medical Meanings" Haubrich, William S. Am Coll Phys Philadelphia 1997
3. "The origin of Medical Terms" Skinner, AH, 1970

Esophageal hiatus hernia surgery

An esophageal hiatus hernia (also known as a hiatal hernia) eventually may require surgery. In this case, the objective is three-fold: To bring the abdominal viscera to its proper intraabdominal position (reduction) , to create a pseudovalve to prevent gastroesophageal reflux, and to prevent a recurrence of the herniation.

There have been different  procedures developed to this effect. One of the most popular has been the Nissen fundoplication either trough the open surgery approach or by way of a minimally invasive laparoscopic procedure.

Nissen fundoplication (www.en.wikipedia.org)
Original image courtesy of Wikipedia.org.

This procedure was pioneered by Dr. Rudolf Nissen (1896 - 1981) in 1955.  After reducing the hiatal hernia and repairing the dilated esophageal hiatus, the surgeon creates a gastric wrap around the abdominal esophagus by bringing the fundus of the stomach through a retroesophageal passage, and suturing the fundus to the stomach. (see image). One of the concerns of the procedure is the ligation and transection of the short gastric vessels that pass within the gastrosplenic ligament to allow greater mobility of the gastric fundus and prevent potential avulsion of the short gastric vessels.

Since the introduction of this open procedure in 1955 there have been several variations, such as the "Nissen-Rosetti" procedure, a "loose" fundoplication; the "Toupet" procedure, an "incomplete" fundic wrap, and others, including laparoscopic procedures.

The advent of NOTES (Natural Orifice Transluminal Endoscopic Surgery) has brought a new procedure: Transoral Incisionless fundoplication (TIF), where a pseudovalve is created using an endoscope inserted into the esophagus and stomach through the oral cavity without abdominal  incisions or trocar ports. For more information on this procedure, click here. Clicking on the inferior image will start a six-minute video of the TIF procedure and the EsophX device.


The term [hiatus] derives from the Latin word [hiare], meaning to "gape" or to "yawn". In human anatomy this term is used to mean an "opening" or a "defect". It must be pointed out that in anatomy (and surgery) the term "defect" does not necessarily mean "defective". In most cases a "defect" is a normal opening in a structure, such as the esophageal hiatus. The plural form is either [hiatus] or [hiatuses].

There are many hiatuses in the human body, such as:

• Hiatus semilunaris: a crescent-shape opening in the lateral aspect of the nasal wall
• Esophageal hiatus: an opening in the muscular posterior aspect of the respiratory diaphragm, bound by two muscular crura
• Aortic hiatus: an opening in the posterior aspect of the respiratory diaphragm, bound by two tendinous crura
• Hiatus Fallopii: the entrance to the facial canal, an opening in the temporal bone allowing for passage of the facial nerve (CN V). Named after Gabrielle Fallopius

Respiratory Diaphragm

The respiratory diaphragm is a musculotendinous dome-shaped shelf that divides the thoracic cavity from the abdominal cavity. It is one of the four named diaphragms in human anatomy. This is why it is proper to call it the "respiratory diaphragm" instead of just "diaphragm".

The name comes from the Greek, where the prefix [dia-] means "complete" or "through" and [phragm] means "a partition". In Latin, Celsus called it the "septum transversum", meaning "the transverse partition". The root term for [diaphragm] is [-phren-], as in phrenic nerves and cardiacophrenic vessels.

The respiratory diaphragm has a club-shaped central tendon (as in a card suit) which has a large hiatus for the inferior vena cava. The muscular portion is formed by skeletal (voluntary) muscle and descends skirt-like to attach to the internal aspect of the sternum and ribs anterolaterally, and a complex system of lumbocostal tendinous arches posteriorly.

Respiratory diaphragm (www.bartleby.com)
Images and links courtesy of Bartleby.com
It receives its blood supply through branches of the intercostal arteries, the musculophrenic artery, and the pericardiacophrenic arteries. It is innervated by the phrenic nerves, which descend through the mediastinum in relation to the pericardium.

The respiratory diaphragm has not one, but seven openings (hiatuses) to allow for passageway of many structures:

• Esphageal hiatus
• Aortic hiatus
• Inferior vena cava hiatus
• Hiatuses (2) for the superior epigastric vessels, which are the inferior continuation of the internal thoracic (mammary) vessels. Also known as the hiatuses of Morgagni.
• Hiatuses (2) for the splanchnic nerves

The most common site for an internal abdominothoracic herniation is the esophageal hiatus, but there are other respiratory diaphragm hernias, including the retrosternal hernia of Morgagni (through the superior epigastric hiatus), and the hernia of Bochdalek (a congenital hernia through an incomplete central tendon of the respiratory diaphragm).