How to Understand Medical Terminology

When studying and using medical terminology it is important to understand the basic structure of medical terms and their meanings. In medicine all parts of a medical term are essential to the meaning of that term and each part of that term has its own meaning.
When learning about language and medical terminology, it is worthwhile remembering that words will contain patterns and the more you read and become familiar with them, the more you will readily and easily understand them. It is also important to note that not every medical term follows the exact same pattern. Some words have very clear derivatives whereas others are not so distinct in in where they have evolved from. Do not expect to see that exact same patterns in all words.

Medical terms sometimes consist of three parts - a root, a prefix and a suffix. When the three are combined it will express the meaning of the term. These types of words are called constructed words as they usually contain all three elements i.e. prefix, root and suffix.

The root of a word (known as the word root) contains the basic meaning (definition) of the word often referring to a body part or system e.g. cardi (heart). There may be more than one word root in a medical term and these are often combined with a combining vowel to make them easier to pronounce.

A prefix may or may not be present, but where it is used, it is placed in front of the word to change its meaning (pre means before), or to identify the core meaning of the word. Example: A prefix added to cardia (heart) will identify the type of heart condition e.g. dextrocardia (dextro means right) so in this case dextrodardia indicates that the heart is on the right side of the body, instead of the common left.

Another example: the prefixes ‘a’ or ‘an’ are much used in medical terminology and mean without for example:

anaemia: an = without/lack of, aemia = blood
anorexia: an = without, orexia pertains to the appetite (anorexia = without appetite).

A prefix may also indicate a time, place, location or status. For example take the term Intravenous meaning “within the veins”. Intra (the prefix) means ‘within’, ven (the word root) means vein, ous (the suffix) means ‘pertaining to’.

A suffix is found after the word root(s) and can also change the meaning or function of the word root. It can modify its forms to a different part of speech (a noun, a verb or an adjective) or may refer to a condition, disorder of a part of the body or medical procedure to treat it. For example, itis is a very common suffix meaning inflammation e.g. arthritis. Another example is ectomy is another well-known suffix that means ‘surgical removal of’ as in appendectomy (removal of the appendix).

Combining vowels can also be used to combine a word root with another word root that indicates location. Take the term pneumothorax as an example. Pneum means, air, lungs, and gas; thorax is the space in the body located between the abdomen and the neck that includes the lungs, the heart, and the first section of the aorta. So pneumothorax means abnormal air or gas in the pleural cavity - the cavity that surrounds the lungs. So the suffix thorax locates the area of the body with the abnormal air/gas.

Not all medical terms comprise of all three parts, some contain only a prefix and a suffix without a root word, or they contain two root words that are bound together by using a combining vowel (often an ‘o’). An example here is cardiovascular. Cardi meaning the heart, vascular meaning the vessels containing blood. Another example of this is cardiopulmonary; cardi means heart, pulmonary means lungs. Once again using cardi (the root word): in cardiotomy - the suffix ‘otomy’ means incision and cardi means heart, so the word cardiotomy means a surgical incision into the heart. The ‘o’, or any combining vowel, does not have a meaning, it is purely used to combine the two words and make them easier to pronounce.

Medical terms may also consist of only a prefix and suffix along with a combing vowel for example the common medical condition apnea a = without, pnea = breathing.

Constructed words are easy to deconstruct and easier to learn as each part has a meaning. Learning the meaning of each word part first makes it much simpler to learn and to understand the meaning of a medical term.

Some medical words are not constructed from the suffix, root and prefix combination. These words are known as non-constructed medical terms. Non-constructed terms cannot be deconstructed into their individual word part so you must memorise them in their totality. They are words derived from other languages (particularly Latin or Greek), acronyms, abbreviations they also include eponyms i.e. medical terms named after the person who discovered the medical condition or procedure.
Study this further with our Medical Terminology Course.
Our Medical Terminology Dictionary is also a great reference.