Plaintiff assigns error to the trial judge’s entry of directed verdict in favor of defendants. The trial judge was correct in *698granting defendants’ motion for a directed verdict if plaintiff’s evidence, considered true and with the benefit of every inference resolved in her favor, failed to establish all of the following elements: (i) the standard of care required of defendant physician; (ii) breach of the standard of care; (iii) proximate cause; and (iv) damages. Lowery v. Newton, 52 N.C. App. 234, 278 S.E. 2d 566, reconsideration of denial of discretionary review denied, 304 N.C. 195, 291 S.E. 2d 148 (1981). Accord, Mitchell v. Parker, 68 N.C. App. 458, 315 S.E. 2d 76, review denied, 311 N.C. 760, 321 S.E. 2d 140 (defendant Hall), 311 N.C. 760, 321 S.E. 2d 141 (defendant Parker) (1984).

We find the trial judge’s entry of directed verdict for defendants was proper because plaintiff failed to present any evidence to support the allegation that defendants’ treatment was the proximate cause of her gangrene which necessitated the amputation. Dr. Fleishman, plaintiff’s expert witness, testified that plaintiff’s amputation was necessary because of her severe peripheral vascular disease. Dr. Fleishman thoroughly examined plaintiff’s left foot on 23 April 1980 and found no evidence of a cut. There was also no mention of a cut in the pathologist’s report. Dr. Fleishman testified:

Q. What you are telling the jury is that this lady lost her leg because of her peripheral vascular disease and because of diabetes, not because of a cut alleged to have occurred on April 21, 1980?

A. [Dr. Fleishman]: That is my opinion, sir.

Q. Doctor, in your opinion this lady’s leg that was amputated by you, this amputation was not caused by any podi-atric care that was either given or not given by either Dr. Tucker or Dr. Healy, is that correct?

Mr. Webster: Objection.

Court: Overruled.

A. [Dr. Fleishman]: No, I don’t think that was caused by her podiatric care.

*699Notwithstanding, Dr. Fleishman’s - isolated deposition testimony in response to a hypothetical question that if the toe were cut, “it could be a contributing factor” his testimony considered in its entirety manifests a positive opinion that defendants’ treatment was not a proximate cause of plaintiff’s injury. See Largent v. Acuff 69 N.C. App. 439, 317 S.E. 2d 111, review denied, 312 N.C. 83, 321 S.E. 2d 896 (1984). An expert witness is allowed to conform his answer to his true opinion, id., and that opinion may be based, in whole or in part, on personal knowledge or observation. See Ballenger v. Burris Industries, Inc., 66 N.C. App. 556, 311 S.E. 2d 881, review denied, 310 N.C. 743, 315 S.E. 2d 700 (1984).

Considered in the light most favorable to plaintiff, and giving plaintiff the benefit of every reasonable inference, plaintiff has failed to introduce any evidence of proximate cause; the directed verdict entered for defendant is, therefore,

Affirmed.