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Dilation vs. Dilatation

Do you treat “dilation” and “dilatation” as synonyms?

According to Dorland’s Medical Dictionary:

  • Dilation is the act of dilating or stretching. It may be a normal physiologic process done by muscles or a therapeutic process done by dilators.

  • Dilatation is the condition, as of an orifice or tubular structure, of being dilated or stretched beyond the normal dimensions.

As you can see, these terms are not synonyms, yet their definitions seem to overlap at times. The main difference seems to be that dilation refers to an action, and dilatation refers to a state.

A few weeks ago, I was discussing this topic on Twitter when I was approached by a professor from the University of Montreal. In our conversation, that professor suggested that it could be a case of haplology — the omission of a syllable for reasons of euphony.

That led me to a paper by John H. Dirckx, MD, called Pronounced Differences, where the following is stated:

“Haplology refers to the phonetic simplification of a word by removal of what may seem to be a redundant syllable.

Many instances of haplology have received formal acceptance (dilation for dilatation, urinalysis for urinanalysis), while others are still waiting for it (adaption for adaptation, cephalgia for cephalalgia).“

I have a question for my readers:

Do you agree with this point of view and, therefore, believe that dilation and dilatation are just two different ways of referring to the same concept?

Considering how accurate, clear, and precise medical communication must be, I am afraid I have to disagree with the idea presented above because those terms refer to two different ideas — an action (dilation) and a state (dilatation).

Yet, I agree that “dilation” is definitely easier to pronounce and sounds better than “dilatation.”

Let me know what you think!


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