Which combining form relates to the arachnoid membranes?

• A. Mening/o
• B. Menin/i
• C. Mening/i
• D. Iatr/o

Answer: (B)

The arachnoid membranes are one of the meninges, the protective coverings of the brain and spinal cord. The term for these membranes comes from the singular form meninx, with meninges as the plural. From that root, the combining form built as mennin- plus the vowel i (menin/i) is used to denote the meninges themselves. Because the question targets the membrane layer within the meninges, this form directly references that tissue, making it the most precise choice. The other options either use related stems or refer to different medical concepts, so they don’t align as tightly with the arachnoid membranes.