What is the test for medical malpractice under the Eighth Amendment?

Plaintiff suffered severe pain in his shoulder for which medical staff prescribed various medications, including morphine. Eventually, an M.R.I. revealed "substantial" damage. Plaintiff was medically restricted. This adequately describes a serious medical need and thus satisfies the first element of his Eighth Amendment medical treatment claim. See Doty v. County of Lassen, 37 F.3d 540, 546 (9th Cir. 1994) ("serious" medical conditions are those a reasonable doctor would think worthy of comment, those which significantly affect the prisoner's daily activities, and those which are chronic and accompanied by substantial pain).