Which prefix is used to denote four parts, as in quadriplegia?

• A. Quad-
• B. Bi-
• C. Tri-
• D. Hemi-

Answer: (A)

The concept being tested is how numeric prefixes convey quantity in medical terms. The prefix that means four is quad- (often seen as quadri- in combined forms). In quadriplegia, four limbs are paralyzed, so the term explicitly signals four parts being affected. That makes quad- the best fit for indicating the number of parts involved. The other prefixes indicate two parts (bi-), three parts (tri-), or half (hemi-), which do not describe paralysis of all four limbs. Quad- is commonly used in terms referring to four, which reinforces its meaning.