Which prefix indicates a direction 'toward' in medical terminology?

• A. ab-
• B. ad-
• C. uni-
• D. dis-

Answer: (B)

The prefix that indicates a direction 'toward' in medical terminology is "ad-." This prefix derives from Latin, where "ad" means "to" or "toward," conveying movement in the direction of something. In medical contexts, it is often used to describe processes or movements directed toward a specific area or structure, such as in terms like "adduct" which refers to moving a limb closer to the body.

In contrast, other prefixes convey different meanings: "ab-" indicates movement away from a reference point, "uni-" signifies one or single, and "dis-" typically implies separation or removal. Understanding these prefixes is essential, as they help in accurately interpreting medical terms and their implications in clinical practice.