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

In most of the human species the PDA arises from the right coronary artery, (see acompanying 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 coranary arteries.

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!

Jan Evangelista Purkinje (1787 - 1869). Known by his German name Purkinje, or his Czech name, Purkyn?, as well as his church-given name Salverius. Purkinje was born in the city of Libochovice, Bohemia, (now Czechoslovakia). He started his early studies in the church with Piarist monks. He took the name of Brother Salverius and served as a teacher in the Piarist schools. He dedicated himself to the study of natural sciences. Purkinje left the monastery before taking his final vows.   Purkinje continued his studies and graduated in medicine in Prague. Even as a student Purkinje started research on the physics of sound and the physiology of vision, which he continued after his graduation. Purkinje was one of the first to understand the vision of motion, thus creating the first animated cartoons!

In 1823 Purkinje was appointed Professor of Physiology at the University of Wroclaw (Breslau), later taking the same chair in Prague. Besides being one of the first to propose experimental physiology as basis for research, Purkinje was one of the first to use the microscope to study the cells of the body, proposing the "cell theory", and introducing the word "protoplasm".

• Purkinje's cell of the cerebellum: Piriform cells found in Purkinje's layer
• Purkinje's fibers of the heart: These are not "fibers" as the name implies, but fast-conducting myocardial cells found as the most distal components of the conduction system of the heart
• Purkinje's law of vertigo: An observation that the apparent motion perceived when stopping the head after rotation changes from horizontal to vertical if the head is inclined laterally. This is important to pilots, as they are trained to understand that in conditions without external reference, moving the head down or laterally can induce uncontrollable vertigo.

Sources:
1. "Purkinje JE (1845) Mikroskopisch-neurologische Beobachturgen" Arch Anat Physiol Wiss Med II/III:281-295
2. "Jan Evangelista Purkinje (1787-1869)" J Neurol Neurosurg Psychiatry. 1994 July; 57(7): 777 
3. "Jan Evangelista Purkinje (1787-1869)" Davies, MK; Hollman A. Heart (1996) 76(4): 311

The root term [-angi-] has Greek origins and means "vessel", as in a "container". The suffix [(o)gram] means "examination of", or a "record". An angiogram is the examination of a vessels using some type of viewing or recording device.

In an angiogram the physician will inject radiopaque contrast to make the vessels discernible in an X-ray machine.

The accompanying image is an angiogram of the right coronary artery. It can also be called a "coronariogram".

The "acute margin" refers to the anteroinferior border of the heart. It is also known by its Latin name [margo acutus].

The name of this border or margin of the heart is quite descriptive. If you observe the angle formed between the anterior or sternocostal surface of the heart with the posterior or diaphragmatic surface of the heart, you can see that the angle between these two surfaces is less than 90 degrees, therefore an "acute" angle. The corresponding border between these two surfaces has to be called the "acute margin"!

In relation to the acute margin of the heart there is usually found one of the longest branches of the right coronary artery. This artery that runs alongside the acute margin, is the "acute marginal artery", In an angiogram, this artery clearly depicts the anteroinferior border of the heart.

Click on the image for a larger depiction. Here is a link to the article on the "obtuse margin" of the heart.

The posterolateral artery, also known as the "retroventricular artery" is one of the two terminal branches of the right coronary artery. The other terminal branch is the posterior interventricular artery or PDA. This artery presents with many variations, from being absent to extremely long arteries with extensive branching that take some of the territory of the circumflex artery. The posterolateral artery extends from the crux cordis to the left side of the heart in the atrioventricular sulcus.

The AV node artery, which provides blood supply to the AV node (a component of the conduction system of the heart) may arise from the posterolateral artery instead of arising from the right coronary artery or the posterior interventricular artery.

When present, the posterolateral artery provides some posterior left ventricular branches and maybe some posterior left atrial branches. See the accompanying image, you may click on the image for more information. The image depicts a posterolateral artery slightly longer than usual.

Image property of: CAA.Inc. Photography: Efrain Klein