The combining form meaning pertaining to dura mater is which?

• A. Dur/o
• B. Cephal/o
• C. Nat/o
• D. Chlor/o

Answer: (A)

This tests recognizing which combining form names the dura mater, the tough outer membrane of the brain and spinal cord. The combining form for dura mater is dur/o, used in terms like dural or subdural to indicate relation to or location near the dura. The other options point to unrelated concepts: cephal/o is head, nat/o is birth, and chlor/o is green. So dur/o correctly denotes the dura mater.