[¶ 1] Gary D. Klimple appealed from a summary judgment dismissing his personal injury action against Mark Bahl. We affirm because Klimple presented insufficient admissible evidence to create a genuine issue of material fact on the issue of whether the motor vehicle accident proximately caused or aggravated Klimple’s Ki-enbock’s disease.
I
[¶ 2] On October 1, 2001, Klimple and Bahl were involved in a motor vehicle acci*258dent in Minot in which Bahl’s vehicle struck Klimple’s vehicle. In April 2004, Klimple sued Bahl, alleging his left wrist and palm were fractured in the accident, Bahl negligently operated his vehicle, and Bahl’s negligence proximately caused his injuries.
[¶ 3] After depositions were taken, Bahl moved for summary judgment in January 2006, claiming there were no genuine issues of material fact for trial because there was no evidence Bahl caused Klim-ple’s injuries. Evidence was presented that a physician diagnosed Klimple after the accident as having preexisting Kien-bock’s disease. Klimple also had been seeking medical treatment for pain in his left wrist before the accident. A physician testified in a deposition that he could not say “with any reasonable degree of certainty” whether the Kienbock’s disease was, or was not, caused by the car accident, but that preexisting Kienbock’s disease “[c]ould have been aggravated by the car accident.” Klimple testified in a deposition that his left wrist was thrust against the door panel during the collision and that he was healthy before the accident but was unable to work after the accident. The district court granted summary judgment in favor of Bahl, concluding Klimple “cannot prove that the automobile accident ... either caused his Kienbock’s disease or aggravated his Kienbock’s disease.”
II
[¶ 4] Summary judgment is a procedural device for the prompt resolution of a controversy on the merits without a trial if there are no disputed issues of material fact or inferences that can reasonably be drawn from undisputed facts, or if the only issues to be resolved are questions of law. Ramsey Fin. Corp. v. Haugland, 2006 ND 167, ¶ 12, 719 N.W.2d 346. Whether a district court properly granted summary judgment is a question of law this Court reviews de novo on the entire record. Bernabucci v. Huber, 2006 ND 71, ¶ 14, 712 N.W.2d 323. The party resisting a motion for summary judgment must present competent admissible evidence which raises an issue of material fact. Peterson v. Zerr, 477 N.W.2d 230, 234 (N.D.1991). The nonmoving party cannot rely on speculation, but must present enough evidence for a reasonable jury to find for the plaintiff. Beckler v. Bismarck Pub. Sch. Dist., 2006 ND 58, ¶ 7, 711 N.W.2d 172.
[¶ 5] “Summary judgment is appropriate against parties who fail to establish the existence of a factual dispute on an essential element of a claim on which they will bear the burden of proof at trial.” Heart River Partners v. Goetzfried, 2005 ND 149, ¶ 8, 703 N.W.2d 330. To succeed in his negligence action, Klimple must prove Bahl owed him a duty, Bahl failed to discharge that duty, and Klimple suffered an injury that was proximately caused by Bahl’s negligence. Perez v. Nichols, 2006 ND 20, ¶ 6, 708 N.W.2d 884. “A proximate cause is a cause which, in natural and continuous sequence, produces the injury and without which the injury would not have occurred.” Rued Ins., Inc. v. Blackburn, Nickels & Smith, Inc., 543 N.W.2d 770, 773 (N.D.1996). When a defendant’s negligence aggravates a preexisting injury, the defendant must compensate the victim for the full extent of the aggravation but is not liable for the preexisting condition itself. Olmstead v. First Interstate Bank, 449 N.W.2d 804, 808 (N.D.1989). Negligence involves questions of fact and is generally inappropriate for summary judgment unless the evidence is such that a reasonable factfinder can reach only one conclusion. Beckler, 2006 ND 58, ¶ 9, 711 N.W.2d 172.
*259[¶ 6] In his deposition, Klimple agreed that the only injury he claimed was caused by the accident was to his left wrist, and during the summary judgment proceedings, the parties focused solely on the narrow question of whether the October 1, 2001, accident caused or aggravated Klimple’s Kienbock’s disease. Kienbock’s disease is the death of a small bone in the wrist from an unknown cause, and has been technically defined as “osteonecrosis of the lunate bone resulting from unknown etiology, although can occur after trauma.” PDR Medical Dictionary 516 (2nd ed.2000). Unlike professional malpractice actions, there generally is no requirement in ordinary negligence cases for expert testimony to establish the elements of the tort. See Johansen v. Anderson, 555 N.W.2d 588, 594 (N.D.1996). In some circumstances, however, expert testimony may be required to resolve issues in an ordinary negligence action. See Bachmeier v. Wallwork Truck Ctrs., 507 N.W.2d 527, 535 (N.D.1993); Day v. General Motors Corp., 345 N.W.2d 349, 358 (N.D.1984). This Court has indicated expert testimony is required if the issue “is beyond the area of common knowledge or lay comprehension,” Leno v. Ehli, 339 N.W.2d 92, 99 (N.D.1983), or the issue “is not within the ordinary experience of the jurors.” Holecek v. Janke, 171 N.W.2d 94, 103 (N.D.1969). Klimple has not argued the causal relationship between the accident and his Kienbock’s disease is a matter within the common knowledge or comprehension of a layperson. See, e.g., 11A Blashfield Automobile Law and Practice: Trial Evidence § 431.5, at 384 (4th ed.2004) (footnote omitted) (“Blashfield ”) (“Opinions on most matters related to bodily injury are naturally beyond the ken of the factfinder, and thus are properly stated by qualified medical experts.”). Consequently, expert medical testimony was required to establish proximate cause in this case.
[¶ 7] The record reflects Klimple has owned a tree service in Minot since 1998 and he and his wife trim and remove trees and grind tree stumps for customers. On September 11, 2001, Klimple went to the clinic complaining of discomfort in his left wrist. He “denie[d] any direct trauma”; the doctor diagnosed him with tendonitis and prescribed heat, rest, and medication. On September 19, 2001, Klimple returned to the clinic, again complaining of pain in his left wrist. The doctor assessed Klimple as having tendonitis and stated in the clinic note that “I do not believe there is any reason for x-rays without any evidence of trauma.”
[¶ 8] When the accident occurred on October 1, 2001, Klimple was driving with his left hand on the steering wheel and, upon impact, his left wrist “kind of bounced against the door and the steering wheel.” Klimple did not perceive any injuries at the scene of the accident and did not report any to the police. Klimple testified that, on the following day, his left wrist was “stiff’ and he “couldn’t even move my hand to speak of.” Klimple made an appointment to meet with an orthopedic surgeon, Dr. Uthus, on October 8, 2001. After reviewing an X-ray, Dr. Uthus .diagnosed a fracture in Klimple’s left wrist and the presence of “[preexisting Kienbock’s disease.” After placing Klimple’s wrist in a cast until December 2001 and ordering physical therapy, Dr. Uthus determined Klimple needed surgery to repair the injury and referred him to Dr. Jeffery Keim, a plastic surgeon and hand specialist. Dr. Keim ordered an MRI of Klimple’s wrist which confirmed Dr. Uthus’s diagnosis of Kienbock’s disease, and Dr. Keim performed surgery in January 2002.
*260[¶ 9] In his deposition, Dr. Keim testified about the nature of Kienboek’s disease and whether the accident caused or aggravated Klimple’s condition:
Q. Okay. What’s the cause of Kien-bock’s?
A. It’s avascular necrosis, loss of the blood supply felt to be due to fractures and nonunion of fractures.
Q. Is this something that a person like Mr. Klimple could get in a car accident?
A. Yes. One of the main theories is trauma and fractures in the lunate.
Q. Okay. And this car accident was on October 1, 2001, and you first saw him December of that same year?
A. Yeah. The car accident was October 1, 2001, and I saw him in December.
Q. Is that enough time for the Kien-bock’s disease to develop to Stage 3?
A. Well, Dr. Uthus felt that he had preexisting Kienbock’s.
Q. And you agreed to that diagnosis?
A- At the time that I saw him, yes.
Q. Doctor, would you agree with me that patients can have Kienbock’s disease months or years before seeking treatment?
A. Yes.
Q. Would you agree that it’s more prevalent in people that use their hands for work? Heavy labor?
A. I wouldn’t say that. It’s more prevalent in men and it’s more commonly related to trauma, repeated trauma, repetitive type trauma.
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Q. Doctor, is it possible that the motor vehicle accident may have caused the increase in Mr. Klimple’s pain complaints?
A. Yes.
Q. Is it also possible that that — this increase in his pain complaints reflect progress of his preexisting Kienbock’s disease?
A: Possibly, yes.
Q. Does the lunate fracture precede the Kienbock’s disease?
A. Yes.
Q. He must have had a broken lu-nate at some point?
A. Well, the fractures of the lunate are a part of the diagnosis of Kienbock’s because the fractures interrupt the blood supply and that results in the necrosis, or dying of the bone.
Q. So I can understand, I think what you’re saying is the lunate is fractured and cuts off the blood supply?
A. Right.
Q. And that’s how the Kienbock’s develops?
A. Yes.
Q. If he had preexisting Kienbock’s disease, he must have fractured the lu-nate at some time before the car accident?
A. Yes.
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Q. Let me ask it to you this way then. Can you say with any reasonable degree of certainty whether Kienbock’s disease was caused in the car accident or not?
A. No.
Q. You just don’t know; right?
A. No.
Q. You’re kind of the repairman after the fact; right?
A. Right.
Q. And I’m not trying to degrade your profession by saying that.
A. No. No. I can’t say whether it was caused in the car accident. Essentially he has a diagnosis of Kienbock’s. *261Could have been aggravated by the car accident.
Q. You just don’t know; correct?
A. Right.
Q. And at Stage 3, I think you told me that he’s going to need surgery, anyway; right?
A. Right.
Q. So he would have been at Stage 3 without the car accident, he still would have needed surgery; right?
A. Yes. Yes.
[¶ 10] In his deposition, Klimple testified his condition became worse after the accident:
Q. Okay. Mr. Klimple, are you able to perform all your daily and customary activities?
A. No.
Q. What can’t you do?
A. Run a saw for a full day.
Q. Again, you’re talking about chain saw?
A. Chain saws, yes.
Q. And you were able to do that before the accident?
A. Yes.
Q. How long — before the accident how often did you have to run a chain saw all day?
A. Every day.
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Q. Anything else that you can’t do now that you could do before the accident?
A. Well, like I said, I used to be able to hold onto branches and — out of the bucket and control them and just let them down, but I can’t do that anymore. I use a rope now.
Q. Anything else?
A. I can’t climb. I used to climb. I can’t do that anymore. Because I won’t trust it with one hand.
Q. Climb what?
A. Trees. In a tight yard where you can’t get a truck in, I used to climb and take them down.
[¶ 11] Bahl argues, and the district court ruled, Klimple cannot establish the causation element of negligence because the record lacks medical testimony stating “to a reasonable degree of medical certainty” that Klimple’s Kienbock’s disease was either caused by or aggravated by the accident.
[¶ 12] This Court has long required that expert medical opinions be expressed in terms of reasonable medical certainty, not mere possibilities. See, e.g., Kunnanz v. Edge, 515 N.W.2d 167, 172 (N.D.1994); Nelson v. Trinity Med. Ctr., 419 N.W.2d 886, 892 (N.D.1988); Smith v. American Family Mut. Ins. Co., 294 N.W.2d 751, 763-64 (N.D.1980); Dehn v. Otter Tail Power Co., 251 N.W.2d 404, 412 (N.D.1977); Holecek, 171 N.W.2d at 100; Grenz v. Werre, 129 N.W.2d 681, 689 (N.D.1964); Vaux v. Hamilton, 103 N.W.2d 291, 295 (N.D.1960); 11A Blashfield § 431.5, at 394-95 (footnotes omitted) (“The opinion of causation must be adequately founded, and generally must be stated in terms of reasonable medical certainty.”). Although hy-pertechnical words are not necessary for admission of expert medical testimony, the test for admissibility “is whether the expert’s testimony demonstrates the expert is expressing a medical opinion that is more probable, or more likely than not.” Kunnanz, 515 N.W.2d at 173. Here, Dr. Keim testified only that the accident “[p]ossibly” caused or “[c]ould have” aggravated Klimple’s Kienbock’s disease. Dr. Keim’s testimony does not constitute an admissible medical opinion that the Ki-*262enbock’s disease was, more likely than not, caused by or aggravated by the accident.
[¶ 13] Klimple acknowledges the “equivocal" nature of Dr. Keim’s testimony on causation, but argues that the doctor’s testimony, considered together with his own testimony of the condition of his wrist before and after the accident, raises a genuine issue of material fact on proximate causation. Klimple relies on cases from other jurisdictions holding proximate cause in an ordinary negligence case may be established by medical evidence of “possible” causation combined with other evidence, including plaintiffs’ testimony about them physical condition before and after an accident. See, e.g., Guyer v. Mayor and Aldermen of the City of Savannah, 162 Ga.App. 598, 292 S.E.2d 445, 448 (1982) (medical testimony that injury “may be causally related” to collision coupled with plaintiffs testimony about effect on her work precluded summary judgment dismissal); Roberson v. Hicks, 694 N.E.2d 1161, 1163 (Ind.Ct.App.1998) (internal citations omitted) (“Standing alone, an expert opinion which lacks reasonable probability is not sufficient to support a verdict ... However, ‘an expert’s opinion that something is “possible” or “could have been” may be sufficient to sustain a verdict or award’ when rendered in conjunction with other, probative evidence establishing the material factual question to be proved.”); see also 11A Blashfield § 431.5, at 396-97 (footnotes omitted) (“it has been held that [medical] opinions may be stated in terms such as ‘might have caused’ or ‘could have caused’, where supported by other competent proof of causation”). We decline to adopt the reasoning of these cases because it conflicts with our caselaw on the admissibility of expert medical testimony and the competency of layperson testimony.
[¶ 14] In Asch v. Washburn Lignite Coal Co., 48 N.D. 734, 735, 186 N.W. 757, Syll. 6 (1922) (emphasis added), this Court held that “[t]he injured person is a competent witness to testify to his feelings, pains, and symptoms, as well as to all the characteristics of the injury, so far as the same are perceptible to the senses, and do not require the exercise of scientific skill and knoivledge.” See also Cain v. Stevenson, 218 Mont. 101, 706 P.2d 128, 131 (1985) (“lay testimony is not sufficient to establish cause for those aspects of an injury not apparently related to the accident in question”). We conclude the causal relationship between the accident and Klimple’s Kienbock’s disease is not a matter within the common knowledge or comprehension of a layperson. The incongruity of allowing equivocal medical testimony combined with layperson testimony to prove causation when the causation issue requires admissible expert testimony is explained in Palace Bar, Inc. v. Fearnot, 269 Ind. 405, 381 N.E.2d 858, 864 (1978):
A doctor’s testimony can only be considered evidence when he states that the conclusion he gives is based on reasonable medical certainty that a fact is true or untrue. A doctor’s testimony that a certain thing is possible is no evidence at all. His opinion as to what is possible is no more valid than the jury’s own speculation as to what is or is not possible. Almost anything is possible, and it is thus improper to allow a jury to consider and base a verdict upon a “possible” cause of death.
See also Oxendine v. State, 528 A.2d 870, 873 (Del.1987) (same); Topp v. Leffers, 838 N.E.2d 1027, 1036 (Ind.Ct.App.2005) (plaintiffs testimony in conjunction with expert medical opinions was not sufficient to prove causation because plaintiffs testimony merely established the possibility of causation and the doctor’s opinions lacked reasonable medical certainty); Baughman v. Pina, 200 Or.App. 15, 113 P.3d 459, 460 (2005) (“When the element of causation *263involves a complex medical question, as a matter of law, no rational juror can find that a plaintiff has established causation unless the plaintiff has presented expert testimony that there is a reasonable medical probability that the alleged negligence caused the plaintiffs injuries.... The rule prevents jurors from speculating about causation in cases where that determination requires expertise beyond the knowledge and experience of an ordinary lay person.”).
[¶ 15] Dr. Keim’s deposition testimony, considered together with Klimple’s deposition testimony, raise no more than speculation and conjecture about the cause or aggravation of Klimple’s Kienbock’s disease. Based on the narrow issue presented in this case, we agree with the district court that Klimple failed to raise a genuine issue of material fact that the accident proximately caused or aggravated Klim-ple’s Kienbock’s disease.
Ill
[¶ 16] The summary judgment is affirmed.
[¶ 17] GERALD W. VANDE WALLE, C.J., DALE V. SANDSTROM, and CAROL RONNING KAPSNER, JJ., concur.