In Artal v. Allen (2003) 111 Cal.App.4th 273, the court summarized the principles relating to the statute of limitations for medical malpractice and the assertion of delayed discovery: "Section 340.5 provides 'in an action for injury . . . against a health care provider based upon such person's alleged professional negligence, the time for the commencement of action shall be three years after the date of injury or one year after the plaintiff discovers, or through the use of reasonable diligence should have discovered, the injury, whichever occurs first.' Thus, section 340.5 contains two periods of limitation, a three-year period and a one-year period, both of which must be met. "There is no issue here as to plaintiffs' compliance with the three-year provision of section 340.5. Plaintiffs filed suit less than three years after the August 9, 2008 surgery." (Artal, supra, 111 Cal.App.4th at p. 278, fn 4.) "Under section 340.5, the three-year period is tolled '"(1) upon proof of fraud, (2) intentional concealment, or (3) the presence of a foreign body, which has no therapeutic or diagnostic purpose or effect, in the person of the injured person." The statute makes clear, however, that the one-year period is not similarly extended. Thus, regardless of extenuating circumstances, the patient must bring . . . suit within one year after he discovers, or should have discovered, the "injury." (Sanchez v. South Hoover Hospital (1976) 18 Cal.3d 93, 100-101 (Sanchez).)' (Gutierrez v. Mofid (1985) 39 Cal.3d 892, 896.) "In Sanchez, the Supreme Court 'indicated that by common law tradition, the term "injury," as used in section 340.5, means both "a person's physical condition and its 'negligent cause.'" (Sanchez, supra, 18 Cal.3d at p. 99, citing Stafford v. Shultz (1954) 42 Cal.2d 767, 776-777; , . . . .) Thus, once a patient knows, or by reasonable diligence should have known, that he has been harmed through professional negligence, he has one year to bring his suit.' (Gutierrez v. Mofid, supra, 39 Cal.3d at p. 896.) "The patient is 'charged with "presumptive" knowledge of his negligent injury, and the statute commences to run, once he has "'notice or information of circumstances to put a reasonable person on inquiry, or has the opportunity to obtain knowledge from sources open to his investigation. . . .'" (Sanchez, supra, 18 Cal.3d at p. 101. . . .) Thus, when the patient's "reasonably founded suspicions have been aroused," and she has actually "become alerted to the necessity for investigation and pursuit of her remedies," the one-year period for suit begins. (18 Cal.3d at p. 102.)' (Gutierrez v. Mofid, supra, 39 Cal.3d at pp. 896-897.)" (Artal, supra, 111 Cal.App.4th at pp. 278-279.) The Supreme Court also reiterated that plaintiffs seeking to rely on the delayed discovery rule "'must specifically plead facts to show (1) the time and manner of discovery and (2) the inability to have made earlier discovery despite reasonable diligence.' In assessing the sufficiency of the allegations of delayed discovery, the court places the burden on the plaintiff to 'show diligence'; 'conclusory allegations will not withstand demurrer.' (McKelvey v. Boeing North America, Inc. (1999) 74 Cal.App.4th 151, 160 superseded by statue on another point, as stated in Grisham v. Philip Morris U.S.A., Inc. (2007) 40 Cal.4th 623, 637, fn. 8.)" (Fox, supra, 35 Cal.4th at p. 808.) In Artal v. Allen, the plaintiff truly was unable to appreciate the injury until subsequent diagnosis of broken thyroid cartilage. (Artal, supra, 111 Cal.App.4th at p. 278.) The Artal plaintiff properly pleaded she had discovered the negligent cause of their injury upon the second exploratory surgery. She also pleaded facts showing "that a reasonable investigation at that time would not have revealed a factual basis" for her malpractice cause of action and also pled facts demonstrating her "reasonable diligence." (See Fox, supra, 35 Cal.4th at p. 803.)