This is not just a medical usage.
The suffix ~ac is used when an adjective is created from a noun, and is itself often used as a noun.
Medically, the first usage which springs to mind is "Cardiac Arrest" - this refers to the sudden stopping of the function of the heart...... cardiacus being Latin for 'heart'.
Another is the word sacroiliac, which means relating to the sacrum and the ilium (two of the bones in the pelvis).
The "-ac" is a suffix added mostly at the end of medical words and other scientific words that indicates "relation to". It comes from the French, Latin, and Greek forms and is sometimes related to the suffix "-ic" also. So, in a medical example we could take the word "cardiac". The "-ac" would mean "related to the heart". And so on. Here is a more detailed explanation: http://www.wordinfo.info/words/index/info/view_unit/5
In medical terminology...... -ac = pertaining to The abbreviation "a.c." means = ante cibum or before meals.
anti-coagulant or before meals
Depending on the context, ac can stand for before meals (with regard to medication, for instance) or acromioclavicular (as in the ac joint).
Pertaining to
Pertaining to # Example: Cardiac Means Pertaining to heart
suffix AR = pertaining to
Suffixes that turn the words into adjectives (or pertaining to) are: -ac/-al/-an/-ar/-ary/-eal/-ic/-ive/-tic
-ar is not specifically a medical suffix but is generally used as an adjective suffix in the English language. -armeans "like, nature of, relating or pertains to, belonging to".
Mnemonic using a very visual acronym story to recall -ar: "Does that car (-ar) really (relating to) belong (belonging to) to you?" asks the police officer who is trying to calm down the crowd. And no one thought you could teach your pet LioN (like, nature of) to drive your car. He's doing great but you forgot to teach him how to stop at stop signs and pedestrians.
related to or pertaining to "vascular"
-ar means pertaining to
Ar is not a prefix in medical terms. Ab and Ad are, but not Ar.
-plegia is the medical terminology combining form that means paralysis.
Rachio- is a medical terminology combining form meaning spine.
The medical terminology combining form -crine means secretion
The medical terminology combining form oto- means ear.
Ex- is the medical terminology combining form meaning out or outside.
The medical terminology combining form dolicho- means long or narrow.
The medical terminology combining form burso- means bursa or bursal.
Yes, the medical terminology combining form -plasia means formation.
Yes, the medical terminology combining form -sclerosis means abnormal hardening.
The medical terminology combining form "vis-" refers to vision or sight.
The combining form crani- refers to the skull or cranium.
Ventricul- is the medical terminology combining form meaning ventricle.