Medical Terminology Guidelines
I.
Word Elements
A. root- main part of word; subject of word
B. prefix- at beginning of word
C. suffix- end of word
D. combining vowel- connects parts of words and makes it easier to pronounce
II.
Rules for Combining Word Elements
A. Root cannot stand alone
B. Combining vowel always used with two or more roots are joined
C. No combining vowel with a prefix
D. Combining vowel is usually “o” Ex: oste/o/poro/sis
E. When suffix begins with a consonant, combining vowel is used
F. When suffix begins with “a, e, i, o u”, the “o” on the root is not used.
Ex: oste/o and itis= osteitis
III.
Pronunciation
A. “ch” sounds like “k” Ex: chime, chronic
B. “ps” sounds like ”s” Ex: psychiatric, psoriasis
C. pn” sounds like “n” Ex: pneumonia
D. “c” sounds like a soft “s” when it comes before “e, i, y“ Ex: cycle, cytoplasm
E. “g” sounds like “j” when it comes before “e, i, y“ Ex: giant, gestation
F. “x” at the beginning of words is sometimes pronounced like a “z”
G. “i” at the end of the word is pronounced “eye” Ex: alveoli, villi
IV.
Spelling- always be aware
A. May be pronounced the same, but spelt differently Ex: ilium (part of pelvis ) and ileum (part of
small intestine)
B. Some words sound similar Ex: urethra (tube to urinary bladder) and ureter (tube from kidney)
V.
Changing Singular to Plural
A. Add “-e” to a word ending in “-a” Ex: axilla to axillae
B. Drop the “-ax” at the end of a word and add “-aces” Ex: thorax to thoraces
C. Change the “-x” to “-g” in a word ending in “-nx” and add “-es” Ex: phalanx to phalanges
D. Drop “-ix” or “-ex” at end of the word and add “-ices” Ex: appendix to appendices
E. Drop the “-us” at the end of the word and add “-i” Ex: alveolus to alveoli
F. Drop the “i” at the end of a word and add “ies” Ex: myringotomy to myringotomies
G. Drop the “-on” at the end of a word and add an “-a” Ex: ganglion to ganglia
H. Drop the “-is” at the end of a word and add “-es” Ex: metastasis to metastases
I. Drop the “-um” at the end of the word and add “-a” Ex: ischium to ischia
J. Drop the “-ma” at the end “of the word and add “-mata” Ex: stoma to stomata
VI.
Confusing Prefixes
A. ab- (away from)
B. dys- (difficult, bad)
C. hyper- (excessive)
D. inter- (between)
E. sub- (under)
versus
versus
versus
versus
versus
ad- (toward)
eu- (good, normal)
hypo- (decreased)
intra- (inside)
supra- (above)