Needle length is measured in which unit?

• A. Millimeters
• B. Centimeters
• C. Inches
• D. Meters

Answer: (C)

Inches are used because, in U.S. medical practice, needle lengths are labeled in inches. Clinicians select a length like 1/2", 5/8", or 1" to indicate how deep the needle will reach into tissue, and these fractional inch measurements are standard on syringes and needle packaging. While millimeters or centimeters are metric measures and used in other contexts or regions, they are not the normal way to describe a needle length in typical injections on exams. Meters are far too large for any practical needle length. Therefore, the unit that applies here is inches.