with whom TAYLOR, J. and JOHNSON, S.J., join, dissenting:
¶ 1 I agree with the majority that a nurse may qualify to testify as an expert on the issue of the standard of care practiced by other nurses. I dissent because there is a significant difference between allowing a nurse expert to testify as to the standard of care of other nurses and allowing a nurse expert to testify as to causation in malpractice cases. Today’s majority announcement expands the role of nurses beyond that which the Legislature has been willing to confer, is unsupported by precedent and is contrary to extant jurisprudence.
¶ 2 Three elements are essential for actionable negligence: (1) a duty owed by the defendant to protect the plaintiff from injury, (2) a failure of the defendant to properly exercise or perform that duty, and (3) an injury to the plaintiff directly caused by the defendant’s failure. Thompson v. Presbyterian Hospital, 1982 OK 87, ¶ 7, 652 P.2d 260, 263; Nicholson v. Tacker, 1978 OK 75, ¶ 9, 512 P.2d 156, 158; Rush v. Mullins, 1962 OK 62, ¶¶ 5, 6, 870 P.2d 557, 559. In all but extraordinary cases, medical negligence must be established through expert medical testi*216mony. Johnson v. Hillcrest Health Center, Inc., 2003 OK 16, ¶ 13, 70 P.3d 811, 817; Turney v. Anspaugh, 1978 OK 101, ¶ 20, 581 P.2d 1301.
¶ 3 It is undisputed Nurse Fuller opines as to causation when she asserts that Gaines developed the ulcers as a direct result of the failure of the nurses who were caring for him to meet the requisite standard of care. She further asserts that the development of the decubitus ulcers was preventable if the standard of care had been met, despite the patient’s size, nutritional deficits, and or immobility due to the trauma and surgical complications.1 The specific issue on appeal is whether Nurse Fuller, a registered nurse, qualifies as an expert to testify concerning the cause of the decubitus ulcers suffered by Gaines.
¶ 4 The Oklahoma Legislature has distinctly delineated the roles of physicians and nurses. Physicians are expressly authorized to diagnose and treat diseases, illnesses and injuries. 59 O.S.2001, 192 (C)(3)(a). In contrast, nurses are not authorized to make any type of medical diagnosis. Rather, nurses perform services “for purposes of nursing diagnosis and treatment of human responses to actual or potential health problems consistent with educational preparation.” Title 59 O.S.2001, 567.3a (2) (emphasis added). While each are educated and licensed in their respective fields, physicians diagnose and treat diseases, illnesses and injuries whereas nurses execute the orders of the physicians. Unlike physicians, the Legislature has not provided for nurses to medically diagnose the cause of any medical condition. Nurse Fuller purports to do what the statutes authorize physicians to do, that is, diagnose the cause of a disease. Her affidavit claims that Gaines’s ulcers were caused by the negligence of his nurses and she rules out any other cause. Allowing nurses to offer testimony on causation is equivalent to allowing them to diagnose disease, an act the Legislature has clearly reserved for physicians. See 59 O.S.2001, m (C)(3)(a).
¶ 5 Likewise, this Court has consistently held that physicians, not nurses, are qualified to diagnose diseases and, consequently, testify as to causation. See Shawnee Gas & Electric Co. v. Hunt, 1912 OK 276, ¶ 3, 122 P. 673, 674. In Shawnee Gas & Electric Co., the mother of the plaintiff was a graduate nurse, who testified during the trial that her son was suffering from an epileptic condition, based on her opinion. The Court observed that she had never nursed in cases of epilepsy, and that her testimony as an expert as to what these symptoms indicated was not admissible because there was no proof in the case showing that nurses, as part of their training, were required to learn to diagnose diseases. Id. While Nurse Fuller, in the case now before this Court, may recognize decubi-tus ulcers, there is nothing in the affidavit or the statutes to show that registered nurses are trained in diagnosing the cause of diseases.
¶ 6 The majority goes to great lengths to show that several jurisdictions allow nurses to testify as experts in decubitus ulcer malpractice cases and that Oklahoma would be a “minority of one” if it did not allow such testimony.2 However, the majority fails to distinguish between allowing expert testimony on the standard of care of other nurses and allowing it on the issue of medical causation. This distinction is critical as only two of the nine eases relied on by the majority, all of which are intermediate appellate decisions, actually allowed a nurse expert to testify as to causation. The remaining seven cases, while allowing nurse expert testimony for standard of care purposes, either didn’t address the issue of causation or rejected such testimony outright. In fact, in Bermisa, the majority opinion’s only mention of nurses and expert testimony stated that it was error *217(albeit harmless error) for the nurses’ testimony, offered as lay opinion, to stray into the more “ ‘scientific, technical, or other specialized knowledge’ such that expert testimony would have been required.” State v. Bermisa, 104 Hawai'i 387, 90 P.3d 1256, 1266 (Haw.App.2004). It is unclear how this supposition does anything to bolster the majority’s position.
¶ 7 Despite the majority’s suggestion of a growing trend otherwise, the majority of jurisdictions facing the issue refuse to allow nurse expert testimony on the issue of causation. In Richardson v. Methodist Hospital of Hattiesburg 99-CA-02001-SCT, 807 So.2d 1244 (Miss.2002), the plaintiff brought a personal injury and wrongful death lawsuit against the hospital. The trial court granted the hospital’s motion for summary judgment. The plaintiff had offered as her expert, Crystal D. Keller, a Registered Nurse and Certified Legal Nurse Consultant, who was designated to testify to the appropriate nursing standards of care and deviations from those standards committed by the hospital staff. In addition, the nurse’s report stated that the deviations from the requisite standard of nursing care led to Wheeless’s suffering and subsequent death. Richardson, 99-CA-02001-SCT (¶ 4), 807 So.2d at 1245.
¶ 8 The Supreme Court of Mississippi held that the nurse was qualified to testify concerning deviations in nursing care and resultant pain and suffering, but she was not qualified to testify concerning the causal nexus between those deviations and the patient’s death. Richardson, 99-CA-02001-SCT (¶ 14), 807 So.2d at 1247-1248. In affirming the trial court in part, the Supreme Court observed that the plaintiffs expert had failed to make the required showing that the negligent care by defendant’s nurses had caused or contributed to the patient’s death. Richardson, 99-CA-02001-SCT (¶ 16), 807 So.2d at 1248. The court only allowed the testimony to prove the patient’s suffering.3
¶ 9 The majority opinion blurs the line between standard of care and causation. Although the majority attempts to limit its holding to decubitus ulcer cases, its weak boundaries will soon be eroded entirely, and the door will be opened for a wide variety of medical providers (not just nurses) to render expert opinions as to causation in malpractice cases despite the fact they do not have the requisite training, education or experience to make medical diagnoses. While nurses and other medical care providers provide an invaluable service to patients as well as physicians, the Legislature has placed the responsibility for disease diagnosis squarely on physicians. The majority’s pronouncement impermissibly extends the legislatively-defined role of nurses and fails to value the more intensive training and education required of physicians.
¶ 10 In the case now before us, Nurse Fuller may be competent to testify concerning the standard of care for nurses, and whether the standard was breached, but not whether the breach was the direct cause of Gaines’s ulcers. The trial court correctly determined the plaintiffs proposed nurse expert was unqualified to testify as to the causation of the plaintiffs decubitus ulcers. Because the trial court has wide discretion in ruling on the admissibility of expert testimony, unless that discretion has been abused, the trial court’s decision should not be disturbed. Johnson v. Wade, 1982 OK 32, ¶ 20, 642 P.2d 255, 261. Here, the trial court did not abuse its discretion in finding that Nurse Fuller was not competent to testify as an expert witness concerning the cause of the plaintiffs decubitus ulcers. I would affirm the trial court and, thus, respectfully dissent.
. Affidavit of Susan Fuller, R.N., page 2. Contrary to Nurse Fuller's assertions, Dr. Means testified that, after repairing two abdominal evis-cerations, he instructed nurses not to turn Gaines but to keep "him in bed for a few days flat because I was worried about his guts falling out again.” He further testified in his deposition that Gaines developed the ulcers because of his size and the amount of trauma he sustained. Finally, Dr. Means testified that he had no criticism of the care the nurses provided the patient and concluded that the ulcers were not preventable.
. See ¶ 12 and accompanying footnotes of the majority opinion.
. See also, e.g., Long v. Methodist Hospital of Indiana, Inc., 699 N.E.2d 1164, 1169 (Ind.Ct.App.1998)("the determination of the medical cause of injuries, which is obtained through diagnosis, for purposes of offering expert testimony is beyond the scope of nurses’ professional expertise."); Elswick v. Nichols, 144 F.Supp.2d 758, 765 (E.D.Ky.2001)(nurse not qualified to give opinion on causation because it is equivalent of medical diagnosis); Sandell v. Hooter, 692 So.2d 474 (La.App. 3.1997)(same); Flanagan v. Labe, 547 Pa. 254, 690 A.2d 183, 185 (1997)(only physicians can testify to causation); Colwell v. Holy Family Hosp., 104 Wash.App. 606, 15 P.3d 210, 213-214 (Div. 3 2001)(nurse not allowed to testify as to causation of death blamed on nursing negligence).