A prefix consists of one or two syllables placed before a word in order to modify the meaning of the word. Often these syllables are prepositions or adverbs. Prefixes are commonly used to help describe the appearance of, or the location of, an anatomical part. For example, the term adrenal, the name of a ductless gland above the kidney, is composed of the prefix ad, which means near, and a root renal, which means kidney. Combine the prefix and the root and you get a term that means "near the kidney." Listed below are a few of the prefixes used with common medical terms.

Medical Term Prefix Root Definition
hemiplegia hemi- half
hypodermic hypo- under
intramuscular intra- within