In medical terminology, intra- indicates which spatial relation?

• A. Within
• B. Between two
• C. Too much/too little
• D. Against

Answer: (A)

Intra- means inside or within. It’s used to describe something located inside a structure, as in intracranial (inside the skull), intramuscular (within muscle), or intravenous (within a vein). The other prefixes describe different spatial relations: inter- means between two structures, hyper- or hypo- describe too much or too little, and anti- means against. So intra- corresponds to the idea of “within.”