All of the following are pain insensitive structures except: (A) Choroid plexus, (B) Ventricular ependyma, (C) Brain parenchyma, (D) Falx cerebri
Answer is D. Relatively few cranial structures are pain-producing; these include the scalp, meningeal aeries, dural sinuses, falx cerebri, and proximal segments of the large pial aeries. The ventricular ependyma, choroid plexus, pial veins, and much of the brain parenchyma are not pain-producing. Ref Harrison 20th edition page 85