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The [sphincter of Oddi]  is a complex system of smooth muscles that controls flow of bile and pancreatic juice into the duodenum. Although known by its eponym, this structure has the anatomical name of "sphincter of the hepatopancreatic ampulla". Although described previously by others, it was Ruggero Oddi (1864-1913) who described not only its structure, but also its function.

The hepatopancreatic ampulla or "ampulla of Vater" is a dilation found at the conjunction and end of the common bile duct and pancreatic duct. The presence of the hepatopancreatic ampulla creates a nipple-like elevation of the duodenal mucosa called the "duodenal papilla".

The sphincter of Oddi has several components:

• Sphincter papillae: This portion of the sphincter surrounds the papillary and intramural portion of the hepatopancreatic ampulla
• Sphincter choledochus: This portion of the sphincter surrounds the most distal portion of the common bile duct. It must be noted that this is the narrowest portion of the common bile duct, allowing for potential lodging of bile stones, cause for choledocholithiasis
• Sphincter pancreaticus: This portion of the sphincter surrounds the most distal portion of the pancreatic duct and prevents reflux of bile from the hepatopancreatic ampulla to the pancreatic duct.

The duodenal muscular layer parts to allow passage of the complex formed by the hepatopancreatic ampulla and the sphincter of Oddi, creating a window called the "choledochal window". Longitudinal fibers from the duodenal muscularis externa pass and join to the sphincter of Oddi.

This is a root term of Greek origin. In both presentations [-chol-] or [-chole-] it means "bile" or "gall". The English word "gall" is of Anglosaxon origin and means "bile", referring to its yellowish-green color. The word [bile] is of Latin origin, from [bilis].

These root terms are used in many medical words, such as:

• cholecystitis: [cyst] means "sac" or "bladder", [itis] means "inflammation" or "infection". Gallbladder inflammation
• cholecystectomy: [cyst] means "sac" or "bladder", [ectomy] means "removal". Gallbladder removal
• cholangiogram: [angi] means "vessel", [(o)gram] means "examination". Examination of a bile vessel
• choledocholithiasis: Condition of stones in the bile duct. Click on the link for more information
• cholera: The suffix [-era] is "flow" or "discharge". The term refers to the constant vomiting of bile in patients afflicted with this disease. This term has been heatedly discussed and this is but one of the theories as to the etymology of the word.

In the early days of physiology, yellow bile was considered one of the "four humors" that made up human personality, temperament, and health. A person with an excess of yellow bile would be considered bad tempered, angry, or "choleric". Observe how the root term [chole] also is found in the word "choleric".

Sources:
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

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.

Ruggero Oddi

Ruggero Oddi  (1864-1913). Anatomist and physician, his complete name was Ruggero Ferdinando Antonio Giuseppe Vincenzo Oddi Pampaglini, born on July 20, 1814 in the city of Perugia, Italy.  He studied medicine in the University of Perugia, where he had a keen interest in anatomy and physiology, graduation with a medical degree in 1889. In 1887, as a fourth year medical student Oddi published a paper that would make his name eponymically tied to the sphincter found around the hepatopancreatic ampulla; what today is known as the "sphincter of Oddi". His paper was entitled "Di una Speciale Disposizione a Sfintere allo Sbocco del Coledoco" (On a Special Sphincteric Arrangement at the Outlet of the Common Bile Duct).

Although the circular muscle of the sphincter of Oddi had already been described by Glisson in 1681, Oddi was the one who did a complete anatomical and physiological study of this structure uncovering the fact that it was indeed a sphincter. He continued his studies on the hepatobiliary sphincter until 1894, when he moved to Congo and later back to Belgium. 

Because of his inclination towards metaphysical studies, Oddi started experimenting with drugs on himself and became addicted.

His later life was surrounded by scandal and controversy, because of drug abuse and fiscal mismanagement of University funds. Oddi died in poverty in 1913 and his site of burial is unknown.

Sources:
1. "Ruggero Ferdinando Antonio Guiseppe Vincenzo Oddi" Lukas, M, et al. World J Surg (2007) 31:2260–2265
2. "Ruggero Oddi; To commemorate the centennial of his original article--"Di unaspeciale disposizione a sfintere allo sbocco del coledoco" Ono, K; Hada, R. Jap J Surg, VOL. 18, No. 4 pp. 373-375, 1988
3. "Ruggero Oddi: 120 years after the description of the eponymous sphincter: A story to be remembered" Capodicasa, E. J Gastroent Hepat 23 (2008) 1200–1203
4. "Oddi: The Paradox of the Man and the Sphincter" Modlin, IM; Ahlman, H. Arch Surg 129 (1994) May 550-557
Original image in the public domain, courtesy of the  National Library of Medicine.

Esophagogastric junction

The "Angle of His" refers to the normally acute angle between the abdominal esophagus and the fundus of the stomach at the esophagogastric junction.

This angle is one of the elements that are important in the prevention of gastroesophageal reflux disease (GERD). When the fundus of the stomach gets expanded by air, because of the normal anatomy and relations of the esophageal hiatus, the esophagogastric junction structures are "pushed" from left to right, pushing close the gastroesophageal flap valve or "rosette". There are other mechanisms that add to the sphincter-like action of the esophagogastric junction structures.

The eponym "angle of His" remembers Dr. Wilhem His Jr. (1864 -1934), a German physician and anatomist, who also described the atrioventricular bundle or "Bundle of His", one of the components of the conduction system of the heart.

Thanks to Debbie Donovan for suggesting this post.
Images property of:CAA.Inc. Artist:Dr. E. Miranda

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The term [coronary dominance] is the answer to the following question: From which coronary artery does the posterior interventricular artery (PDA) arise?

In most of the human species the PDA arises from the right coronary artery, (see accompanying image), therefore most humans (70%) are right dominant. The rest are either left dominant (10%) or have balanced dominance (20%). These statistics have significant variation in different studies.

In the case of balanced dominance, there is either a double posterior interventricular artery, where one is a branch of the right coronary artery and the other a branch of the left coronary artery, or a single PDA receiving blood supply from both coronary arteries.

Coronary dominance is important because the interventricular septum receives blood supply from the PDA in its posterior 1/3rd. If the heart is left dominant, all the blood supply of the interventricular septum is dependant on the left coronary artery. In this case, blockage of the left coronary artery can be catastrophic!

There can be interesting anatomical variations in the coronary arteries of the heart. For a detail on these anatomical variations, click here. Heart and coronary artery anatomy is one of the many lecture topics presented by CAA, Inc

Image property of:CAA.Inc.. Artist:Victoria G. Ratcliffe

This is a word of Greek origin. The prefix [a-) means "absence of", or "without". The root term [-phon-] means "sound" or "voice". Aphonia is a pathological absence of voice, and was used by both Hippocrates and Galen.

Do not confuse [aphonia] with [dysphonia], where the prefix [dys-] means "abnormal". In aphonia there is total absence of voice, whereas in dysphonia there is an abnormal voice or "hoarseness" 

As a side note, the word [phonograph] arises from the combination of the root terms [-phon-] and [-graph-], which means "to write". The word [phonograph] does not relate to the playing of a record, but rather to the process of creating one, transforming sound into a wavy line etched on a rotating wax model that is later cast into records. The modern production of sound CD's is similar, where the sound waves are act upon a laser that "burns" the track into a master CD. It is a similar process, but I guess calling creating a CD a type of "phonography" is too old fashion for modern marketing!