There are three basic word elements: prefix, word root (with a combining vowel), and suffix. Not all medical terms contain all three of these elements and some terms contain more than one of each element. At first, this may seem confusing, but it will make sense as the course progresses.
A prefix is located at the beginning of a word. As mentioned before, some medical terms will not contain a prefix. When there is a prefix, the prefix serves to modify the word in some manner. Prefixes usually signify a number, time, position, direction, or negation (absence of).
Let’s look at some examples:
Perhaps you are familiar with the terms prenatal and postnatal. Nat/o is the main part of the word, or combining form, which means birth. Pre- is a prefix which means before. Post- is a prefix that means after. When you put these meanings together, prenatal means before birth and postnatal means after birth.
Another example is febrile, which means with fever. If you add the prefix, a- to febrile, the meaning of the word is completely changed because a- means without. Therefore, afebrile means without or no fever.
As you can see, the prefix can completely change the meaning of a word. Therefore, it is very important to learn the meanings of prefixes to correctly interpret medical terms.
Both prefixes and suffixes are combined with the other basic element of a medical word – the word root/combining form.
After you learn prefixes, suffixes, and the word roots related to the various body systems, you will be able to roughly define the medical term by defining the various word parts. In general, you will define the word parts in the following order:
Define the suffix or last part of the word first.
Next, define the first part of the word which may be a word root or a prefix.
Finally, define the middle part(s) of the word.
So, let’s put that into other words. Define the words in this order:
As an example, look at the word macro/card/ia. Define the suffix or last part of the word first. In this case, –ia means a condition. Next, define the first part of the word which in this case is a prefix, macro-. Macro- means large. Next, define the middle part of the word which in this case is a word root, card. Card means heart. When put together, you get the definition for macro/card/ia: a condition of a large heart. The definitions sometimes have to be refined, but you can use the last, first, middle method of defining a medical term to get a good sense of what the word means.
Convention has us follow three rules for building medical words. Those rules are:
A word root links a suffix that begins with a vowel.
A combining form (WR + CV) links a suffix that begins with a consonant.
When combining two word-roots (which makes a compound word), link them together using the combining form (i.e., the first word root will have a combining vowel added to it that links it to the second word-root).
Let’s take the suffix -itis which means inflammation. The suffix begins with a vowel, so the preceding word root does not use a combining vowel to link it. As an example, take the word root gastr– which means stomach. Link the word root and suffix and you get gastritis. Note that the word does not use the combining vowel “o” to link gastr- and -itis. In other words, the word is not gastroitis.
When the suffix begins with a consonant, use a combining form of the word root (which is the WR + CV) to link to the suffix. Take the suffix –dynia which means pain. The suffix begins with a consonant, so the preceding word root must be in its combining form (WR + CV) in order to properly link the two. As an example, for the word root ot- which means ear, you must add a combining vowel (o) linking it to the suffix, –dynia. You get the word otodynia (ot/o/dynia) which means pain in the ear, or earache. Note the word is not otdynia. It is important to note that in most instances, the combining vowel used to make combining forms is the letter o. There are instances, however, where other vowels will be used.
Finally, you often build compound words in your daily life. An example is base+ball, or baseball. Another example is chalk+board, or chalkboard. When building compound words, you are simply putting two words together to make a new word. In medical terminology, you also will build compound words. In most cases, linking the word roots in medical words to make a compound word requires adding a combining vowel. Here is an example: osteoarthritis (oste/o/arthr/itis). The word roots oste (bone) and arthr (joint) are linked with the combining vowel “o”. To define the word you just built, define the last part first and then the beginning of the word and subsequent terms in order. Following this guideline, osteoarthritis is defined as inflammation (itis) of the bone (oste) and joint (arthr).
Don’t worry if you are still a little bit confused about this process. As we learn more terms and work through the activities, this will become more clear. Eventually, you should feel confident about your ability to build and define medical terms based on their word parts.
One last word of caution: although knowledge of the various parts of medical terms will give you a general idea of the meaning of the term, a medical dictionary will usually provide more detail and specific information relating to the term. For example, the term “appendicitis” can be defined as inflammation of the appendix by its word parts –itis (inflammation) and appendic/o (appendix). If you look it up in a medical dictionary – in this case, Taber’s Cyclopedic Medical Dictionary, 20th edition, the word is defined as “Inflammation of the vermiform appendix, caused by blockage of the lumen of the appendix and following by infection. It may be acute, subacute, or chronic and occasionally is difficult to diagnose because many other illnesses may cause acute abdominal pain.” As you can see, the medical dictionary provides important additional information.
The pronunciation of medical terms can be challenging. Medical dictionaries can be very helpful in providing pronunciation guides. Most dictionaries include phonetic pronunciation in parentheses after the word. The following are some general pronunciation guidelines:
Letters
Guidelines