The defendant, Dr. Stanley Painter, an osteopathic general practitioner, appeals from a judgment entered by the Superior Court (Kennebec County) on a jury verdict finding him negligent in his medical treatment of the plaintiff, Barbara Jacobs, and awarding damages to her and her husband. For the reasons set forth herein, we affirm the judgment in all respects.
Dr. Painter argues that the Superior Court erred in denying his motions for a directed verdict and for judgment notwithstanding the verdict. He also argues that the court erred in denying his motion to enforce the plaintiffs’ voluntary dismissal of their action against him and that a new trial should be ordered because the court did not instruct the jury to apportion liability for damages to the plaintiffs between him and Dr. Amalfitano, the surgeon who performed the operation that resulted in the injuries complained of and who settled with the plaintiffs before trial. We address these arguments in turn.
I.
The Defendant’s Motions for Directed Verdict and Judgment Notwithstanding the Verdict
A. Standard of Review
In reviewing the Superior Court’s disposition of a motion for either a directed verdict or judgment notwithstanding the verdict, we apply the same standard of review. We must determine, in either instance, “whether the verdict can be sustained by any reasonable view of the evidence, including all justifiable inferences to be drawn therefrom, taken in the light most favorable to the party in whose favor the verdict was rendered.” E.g. Buchanan v. Martin Marietta Corp., 494 A.2d 677, 678 (Me.1985); Cyr v. Michaud, 454 A.2d 1376, 1379-80 (Me.1983).
*233 B. Facts
Viewing all of the evidence in the light most favorable to the plaintiffs, the jury would have been warranted in finding the following facts.
On January 15,1980, Mrs. Jacobs, who at that time was 68 years old and leading a relatively healthy and active life for her age, visited Dr. Painter, her family physician since the mid-1970s, concerning a lump that had appeared on her chest. After examining his patient, Dr. Painter tentatively diagnosed Mrs. Jacobs’ condition as a fractured collarbone. That same day, he sent her to the Waterville Osteopathic Hospital to have x-rays taken and to be seen by Dr. Amalfitano, an orthopedic surgeon who had staff privileges at the hospital.
Dr. Amalfitano saw Mrs. Jacobs that day, reviewed the x-rays that had been ordered by Dr. Painter, examined her, and diagnosed her problem as an “anterior ster-noclavicular separation” or dislocation of the collarbone from the sternum. Dr. Am-alfitano surmised that this was a longstanding injury. Mrs. Jacobs did not complain of pain associated with the lump. Dr. Amalfitano discussed with Mrs. Jacobs the option of correcting the separation through surgical repair. His office note regarding the appointment with Mrs. Jacobs stated that he was performing a “consult for Dr. Painter” and that Mrs. Jacobs was to be returned to the care of Dr. Painter.
On the same day, following the visit from Mrs. Jacobs, Dr. Amalfitano telephoned Dr. Painter to discuss the diagnosis and the possibility of surgery. He also followed up the telephone conversation with a letter dated January 22, 1980, in which he explained, in more detail, his diagnosis that Mrs. Jacobs had a separated collarbone. He stated, “It is probably long-standing, has probably been that way for a long time and she’s never noticed it. That would explain why its not painful.” He expressed his concern, however, that the lump could be a tumor and therefore recommended that Mrs. Jacobs be hospitalized and subjected to a few tests “before making other considerations.” The letter also discussed the option of Mrs. Jacobs undergoing surgery if further x-rays confirmed the separation of her collarbone and if she decided to have surgery. Dr. Amal-fitano concluded his letter with the sentence, “Thank you for permitting me to consult.”
On January 25, 1980, having not seen or spoken with Dr. Amalfitano since the January 15, 1980 meeting, Mrs. Jacobs returned to Dr. Painter’s office. At that time, while she was in his office, Dr. Painter telephoned the Waterville Osteopathic Hospital and arranged for her admission on January 27 for the purpose of having surgery.
Mrs. Jacobs was admitted to the hospital on January 27 with Dr. Painter recorded as treating physician. Mrs. Jacobs’ hospital admission card was filled out by Dr. Painter on that day. He noted on the card that Mrs. Jacobs was being admitted “for surgical intervention of a right clavicular head, sternoclavicular joint” and that because of the possibility of malignancy, “we are planning investigation as to possible sources of our lump.”
Dr. Amalfitano arrived at the hospital just after Mrs. Jacobs’ admission and learned, for the first time, that she had decided to have surgery. He appended a note to the admission card that states, “Had seen her for consultation but had not completed to date, referring to previous note I understand that she is to get a bone scan and other studies done at this time.” He also conducted a second examination of Mrs. Jacobs at that time as a “consultation” for Dr. Painter.
On January 29,1980, after being advised by Dr. Painter that Mrs. Jacobs still wanted to have surgery, Dr.¡Amalfitano visited Mrs. Jacobs in the hospital to obtain her consent to the operation. He recommended that she choose surgical repair involving the use of pins to attach her collarbone to the sternum. After Dr. Amalfitano explained certain risks involved in that type of surgery, Mrs. Jacobs signed the “Consent to Operation” form.
The following day, January 30, 1980, Dr. Amalfitano operated on Mrs. Jacobs with the assistance of Dr. Painter. The surgical *234procedure that was carried out involved affixing Mrs. Jacobs’ collarbone to her sternum by inserting what are known as “Stei-man pins.” Following surgery, she was placed in a plaster cast by Drs. Amalfitano and Painter.
For the duration of Mrs. Jacobs’ stay at Waterville Osteopathic Hospital, Dr. Painter was recorded as her treating or attending physician; he never transferred her care to Dr. Amalfitano in writing, which, under the hospital rules, he would have been required to do in order to place her under Dr. Amalfitano’s primary care. The “Admission-Summary Sheet” from the hospital, which was completed at the time of her discharge and signed by Dr. Painter as the attending physician, lists “Consultation with Dr. Amalfitano_”
Mrs. Jacobs was scheduled to be discharged from the hospital on February 7, 1980. Prior to her discharge, however, x-rays revealed that portions of the pins had migrated. One had moved into her lung cavity and the other entered her aorta, the large artery leading to her heart. She was discharged from the Waterville Osteopathic Hospital on February 11, 1980 and transferred to the Osteopathic Hospital in Portland. She underwent emergency open heart surgery on February 12, 1980 to remove the pin that had severed her aorta. During that operation, she suffered cardiopulmonary arrest. She underwent surgery again several times for the installation and removal of pacemakers and for the removal of a portion of a second pin that had migrated into her lung cavity. She eventually was placed in the intensive care unit for nearly one month, at which time she required a mechanical respirator for breathing.
As a result of the foregoing, Mrs. Jacobs suffered permanent injuries. She must wear a permanent heart pacemaker. She also suffers from Parkinson’s disease, memory loss, and has difficulty speaking.
At trial the jury heard undisputed testimony, from both the plaintiffs’ and the defendant’s expert witnesses, that the surgery performed on Mrs. Jacobs for the repair of her collarbone separation was inappropriate; that, in the circumstances of her case, such an operation never should have been performed.
The defendant’s expert witness, Dr. Barrett, an orthopedic surgeon, testified that there is a difference between the treatment of a patient as a “referral” from a general practitioner and treatment of a patient in the context of a “consultation” for a general practitioner. He testified that when a general practitioner sends a patient to a specialist, it is important that the general practitioner make clear whether it is a referral or a consultation, and that it would be detrimental to the treatment of the patient if a general practitioner failed to clarify, one way or the other, the role of the specialist. Dr. Barrett also testified that if a general practitioner “refers” a patient to a specialized surgeon, it is not his responsibility to know the pros and cons of surgery, but if he sends his patient to another doctor for a “consultation,” he has an obligation to review the recommendations of the consultant and to discuss those recommendations with the patient.
The testimony of the plaintiffs’ expert witness, Dr. Garger, an orthopedic surgeon with experience as a general practitioner, was presented to the jury at trial through the admission of pre-trial deposition testimony. Dr. Garger also testified about the distinction between a “referral” and a “consultation.” The substance of his testimony on that distinction and the implications it carried for the treatment of patients was similar to that of the defendant’s expert.
He testified, in addition, that it was “very much incumbent upon [Dr. Painter] to know what the pros and cons of surgery [were] and in this particular case the particular type of surgery.” The fact that the pin could break was something that should have been “well known to him, and apparently wasn’t reasonably well known to him.” Basing his opinion on the premise that “the patient totally relies on her family physician, particularly when that family physician recommends a specific specialist that she go to,” Dr. Garger testified that Dr. Painter deviated from the ordinary *235standard of care required of a general practitioner by failing “to discuss [with Mrs. Jacobs] the option of doing nothing ... and by the same token the risk of [undergoing the operation] as opposed to doing nothing.” He stated that regardless of Dr. Painter’s involvement in the decision that Mrs. Jacobs have surgery, one of Dr. Painter’s deviations from an acceptable standard of care “was his failure to explain to the patient what the results would be of having no surgery at all.”
Dr. Painter testified that he never discussed the pros and cons of the surgery with either Dr. Amalfitano or Mrs. Jacobs. Mrs. Jacobs was unable to recall at trial whether Dr. Painter advised her about the propriety of undergoing surgery. She did recall that Dr. Painter admitted her to the hospital. When asked why he admitted her she testified, “I was going to have the operation, I guess,” but she did not remember which one of the doctors, or if both of them, had told her that she was going to have an operation. Based upon his review of Mrs. Jacobs’ medical records, Dr. Garger testified that the decision to operate on Mrs. Jacobs was made prior to the determination that her lump was not a tumor. Dr. Amalfitano testified that when Dr. Painter admitted Mrs. Jacobs to the Waterville Osteopathic Hospital on January 27, 1980, he did so “for the purpose of operating on her shoulder” and at the time of her admission, Dr. Painter “was the physician primarily responsible for her care.” Dr. Amalfitano also testified that he did not know how Mrs. Jacobs reached the decision to undergo the operation on her collarbone.
C. Law
We have, on several occasions, stated that to prevail in a negligence action, the plaintiff must establish that the defendant was under a duty to conform to a certain standard of conduct and that a breach of that duty proximately caused an injury to the plaintiff. E.g, Rowe v. Bennett, 514 A.2d 802, 804 (Me.1986); Macomber v. Dillman, 505 A.2d 810, 812 (Me.1986).
A defendant physician, whether a general practitioner or a specialist, may be held liable for injuries “caused either by the defendant’s lack of that degree of skill and knowledge ordinarily possessed by physicians in his branch of medicine, or, by his failure to exercise his best judgment in the application of that skill, or, by his failure to use ordinary care in ... administering the treatment involved.” Downer v. Veilleux, 322 A.2d 82, 87 (Me.1974); Josselyn v. Dearborn, 143 Me. 328, 338, 62 A.2d 174, 180 (1948) (a general practitioner “is answerable for injury to his patient proximately resulting from his lack of ordinary skill or from the lack of its application, or from neglect or carelessness in the diagnosis and treatment of the case, or failure to exercise his best judgment”). Subsumed within these general negligence principles is the more particularized theory that physicians can be held liable for medical malpractice by failing properly to advise or inform a patient about the risks inherent in, or the alternatives available to, a proposed course of treatment. See Downer v. Veilleux, 322 A.2d at 89-90; Woolley v. Henderson, 418 A.2d 1123,1128 (Me.1980). To establish a physician’s liability under the latter standard, there must exist a causal connection between the plaintiff's injuries and the negligence of the defendant under an “objective test.” In other words, the factfinder must conclude that a reasonable person in the position of the plaintiff would not have undergone the proposed treatment had that person been properly informed of the risks or apprised of the available alternatives to the treatment that resulted in injuries. See id. at 1132.
In a medical malpractice action premised on the defendant’s failure properly to advise the patient or disclose certain information regarding the course of treatment, “[t]he first element of the plaintiff’s burden is to show that the defendant had a duty to disclose the information [or advice] withheld.” Downer v. Veilleux, 322 A.2d at 90.
The existence and scope of such a duty is not a matter of law, but is governed by medical standards applicable to “a reasonable medical practitioner” in the defendant’s branch of medicine. Compare id, at *23692 (delaying decision “as to whether the duty to disclose is governed by medical or legal standards”) and Woolley v. Henderson 418 A.2d at 1129-31 (reaching a decision on the issue left open in Downer, and holding that “the scope of a physician’s duty to disclose is measured by those communications a reasonable medical practitioner in that branch of medicine would make under the same or similar circumstances”).1 The plaintiff must ordinarily prove the nature and scope of this duty by expert medical evidence. Woolley v. Henderson, 418 A.2d at 1131. It is then up to the jury to decide “whether, under the facts of the case, the physician has deviated from the standard of care of the reasonable practitioner.” Id. at 1130. See Josselyn v. Dearborn, 143 Me. at 339, 62 A.2d at 180.2
D. Discussion
Dr. Painter argues that he was entitled to a directed verdict or judgment notwithstanding the verdict because he disassociated himself from the treatment of Mrs. Jacobs’ collarbone problem by sending her to Dr. Amalfitano on January 15, 1980. He argues that even viewing the evidence in the light most favorable to the plaintiffs, the jury could not have reasonably found that he was involved in the treatment of that problem after that date. He suggests, instead, that the evidence shows that he referred the treatment of Mrs. Jacobs’ dislocated collarbone to Dr. Amalfitano, that Dr. Amalfitano exclusively treated that condition, and that his only medical treatment of Mrs. Jacobs during the time period in question was his care of other aspects of her health unrelated to the dislocated collarbone. As a result, he argues that the jury could not rationally find any duty on his part to advise or disclose information to Mrs. Jacobs about the risks of the proposed surgery or the available alternatives. We disagree.
Undisputed expert medical testimony of both parties established that the existence of Dr. Painter’s duty to Mrs. Jacobs in regard to the treatment of her collarbone condition turned on whether or not he sent her to Dr. Amalfitano as a “referral” or whether Dr. Amalfitano served only as a “consultant.” This was a factual question for the jury. We conclude that the jury could reasonably have found that from the time Mrs. Jacobs first saw Dr. Painter about the lump on her chest on January 15, 1980, through at least January 28, at which *237time she apparently had made her decision to undergo surgery, Dr. Painter was the primary physician responsible for the treatment of her collarbone problem. In that role, he had a duty to discuss with her the option of undergoing surgery, and to advise her about the option of doing nothing.
We also conclude, upon reviewing the facts in the light most favorable to the plaintiff, that the jury could reasonably have found that Dr. Painter breached his duty to Mrs. Jacobs by failing to discuss with her the merits of undergoing surgery. After January 15,1980, no one took responsibility for advising Mrs. Jacobs in her decision about the surgery. She ended up being admitted to the hospital by Dr. Painter for the purpose of having surgery without receiving any professional advice from him or Dr. Amalfitano. From the evidence presented, the jury could conclude that it was incumbent upon Dr. Painter, as the primary treating physician, to discuss the merits of the operation with Dr. Amalfitano and, of greater importance, with Mrs. Jacobs. Moreover, the jury could have reasonably concluded that had he fulfilled his professional obligation to Mrs. Jacobs, he would have recommended, at the very least, that she consider doing nothing at all about the collarbone problem because the problem was cosmetic and the proposed surgery was both inappropriate and unnecessary. Prior to her admission to the hospital, Dr. Painter, the person primarily in charge of her treatment, never discussed with her the option of doing nothing.
Finally, we conclude that the jury could have reasonably found that Dr. Painter's breach of his duty to Mrs. Jacobs proximately caused her injuries. On the facts presented at trial, the jury was warranted in concluding that a reasonable person under the long-term care of a family doctor would choose not to undergo unnecessary surgery if properly advised, before admission to the hospital, that there was a viable alternative to surgery, the option of doing nothing.
E. Conclusion
Having carefully examined the evidence in the light most favorable to the plaintiffs, we conclude that the jury’s verdict is properly supported by the facts.
In sum, there was sufficient evidence to establish that Dr. Painter owed a duty to advise or inform Mrs. Jacobs about the merits of the proposed surgery, the risks involved, or the alternatives available, including the option of doing nothing. There was likewise sufficient evidence for the jury to conclude that Dr. Painter breached his professional duty by failing to so advise Mrs. Jacobs. Finally, the jury could have rationally found, under an objective standard, that the breach of that duty was a proximate cause of Mrs. Jacobs’ injuries.
II.
The Defendant’s Motion to Enforce the Plaintiff's Voluntary Dismissal of their Action Against Him
The defendant next argues that the Superior Court erred in denying his motion to enforce a dismissal filed by the plaintiffs. We disagree.
On October 12,1983, the plaintiffs filed a “Notice of Dismissal Under Rule 41(a)” attempting to voluntarily dismiss Dr. Painter from the case. At that time Dr. Amalfi-tano was a co-defendant in the case. The plaintiffs subsequently filed a withdrawal of their notice of dismissal on October 14. On November 10, 1983, Dr. Painter moved to enforce the plaintiffs’ dismissal. In the same motion he asked for summary judgment contending that because the plaintiffs’ dismissal was effective, and suit was not re-instituted within two years of the alleged negligent conduct, their suit against him was barred by the statute of limitations. The Superior Court denied the motion.
The defendant argues that the Superior Court erred in denying his motion to enforce dismissal because a notice of dismissal once filed cannot properly be withdrawn. We conclude, however, that the plaintiffs’ notice of dismissal was ineffective to terminate the action against the *238defendant and the act of withdrawal was superfluous.
Rule 41(a)(1) of the Maine Rules of Civil Procedure provides in pertinent part:
[A]n action may be dismissed by the plaintiff without order of court (i) by filing a notice of dismissal at any time before commencement of trial of the ac-tion_ A dismissal under this paragraph may be as to one or more, but fewer than all claims, but not as to fewer than all of the plaintiffs or defendants. (Emphasis added.)
Under the clear provisions of Rule 41(a)(1), the plaintiffs’ attempted dismissal of Dr. Painter, without the inclusion of all other defendants in the action, was ineffective. Cf. State v. Northern Products, Inc., 440 A.2d 1070, 1072 (Me.1982) (voluntary dismissal ineffective to dismiss action as to fewer than all plaintiffs). Dr. Painter cannot enforce the plaintiffs’ ineffective notice of dismissal, nor can he rely on an ineffective dismissal to argue that the statute of limitations barred the plaintiffs’ action against him. Thus, the Superior Court correctly denied his motion.
III.
The Defendant’s Proposed Jury Instructions on the Apportionment of Damages between Dr. Painter and Dr. Am-alfitano
The defendant asserts that the Superior Court erred by not instructing the jury, under his proposed special interrogatories, to apportion the damages recoverable by Mrs. Jacobs between himself and Dr. Amal-fitano. This argument is totally without merit.
The allocation the defendant seeks is available only in cases “involving multi-party defendants.” 14 M.R.S.A. § 156 (1980). Thus, in order to make his argument tenable, he attempts to challenge the validity of a stipulated dismissal of Dr. Amalfitano that was approved by the Superior Court over one and one-half years before trial. By the time this case proceeded to the pretrial conference, Dr. Painter had never objected to the court’s order dismissing Dr. Amalfitano from the action. In fact, his objection to Dr. Amalfitano’s dismissal was raised for the first time after trial at a hearing on his motion for judgment notwithstanding the verdict.
The pretrial order of the Superi- or Court established that the only defendant in this action was Dr. Painter. By failing to object either to the dismissal of Dr. Amalfitano before the issuance of that pretrial order or to the pretrial order, itself, the defendant failed to preserve his right to object to that dismissal after trial or on appeal. See Ocean National Bank of Kennebunk v. Odell, 444 A.2d 422, 424 (Me.1982). Since the case did not involve multiple defendants, Dr. Painter was not entitled to have the jury apportion the responsibility for damages between himself and Dr. Amalfitano.3
The entry is:
Judgment affirmed.
McKUSICK, C.J., and ROBERTS and GLASSMAN, JJ., concur.
. As a leading treatise on the law of torts points out, "Under our system of procedure, this question is to be determined in all doubtful cases by the jury, because the public insists that its conduct be judged in part by the man in the street rather than by lawyers, and the jury serves as a shock-absorber to cushion the impact of the law." Prosser & Keeton, The Law of Torts, § 37 p. 237 (5th ed.1984).
. The Superior Court’s instructions to the jury in the case at bar were consistent with the legal principles summarized above.
We note that the court refused to give a jury instruction, requested by Dr. Painter’s counsel, that by signing the "Consent to Operation” form given to her by Dr. Amalfitano, Mrs. Jacobs could not claim that her injuries were proximately caused by Dr. Painter’s failure to adequately advise her about the risks involved in or the alternatives available to the proposed surgery. Dr. Painter’s counsel argued that, pursuant to 24 M.R.S.A. § 2905(2) (Supp.1986), the written consent obtained by Dr. Amalfitano sanitized any prior negligence of Dr. Painter in failing adequately to advise Mrs. Jacobs about the risks of the proposed surgery and the alternatives available. The court rejected that argument on the ground that the information contained in the "Consent to Operation” form did not adequately apprise Mrs. Jacobs of the nature and risks of the surgery. On appeal, the defendant does not challenge the court's refusal to give that requested instruction nor does he suggest that the informed consent statute, 24 M.R.S.A. § 2905, was otherwise improperly applied or ignored by the Superior Court.
His only challenge to the jury instructions is an indirect contention, discussed in the context of the sufficiency of the evidence argument, that the Superior Court should have instructed the jury that to hold Dr. Painter liable for failing properly to advise Mrs. Jacobs of the risks of the operation or the available alternatives, the plaintiffs were required to prove that she would have subjectively decided not to undergo surgery if she had been so advised. This is contrary to our holding in Woolley, where we adopted the "objective test” and said, "The patient’s hindsight testimony as to what he [or she] would have done, though relevant, is not determinative of the issue.” Woolley v. Henderson, 418 A.2d at 1132 (quoting Sard v. Hardy, 281 Md. 432, 450, 379 A.2d 1014, 1025 (1977) (quotations omitted)).
. In any event, the Superior Court properly set off the jury verdict by amounts the plaintiffs previously received from their settlement with Dr. Amalfitano.