Casey, J. Appeal from an order of the Supreme Court (Ryan, Jr., J.), entered March 13, 1992 in Schenectady County, which granted defendant Ellis Hospital Association’s motion for summary judgment dismissing the complaint against it.
Plaintiff Catherine Kadyszewski (hereinafter plaintiff), then 67 years of age, was admitted to the hospital of defendant Ellis Hospital Association (hereinafter defendant) under the care and treatment of her own private attending physician, suffering from left hip and thigh pain of unknown etiology, as well as anxiety and depression. On the evening of December 21, 1985, plaintiff was allegedly medicated by hospital personnel with Demoral, Vistaril, Motrin and phenobarbital. At approximately 4:45 a.m. the following day, plaintiff sustained a fractured left hip when she fell in her room after leaving her bed attempting to walk to the bathroom. Plaintiff avers that she tried for half an hour to summon aid and assistance without any response before attempting to walk to the bathroom on her own. Her action against defendant is based on malpractice and negligence. After issue was joined, defendant moved for summary judgment dismissing both causes of action against it. Supreme Court granted defendant’s motion and plaintiffs appeal.
In support of its motion, defendant filed affidavits demonstrating that the treatment rendered to plaintiff was given under the direction of her own personal physician who was not an employee of defendant, that defendant on its behalf did not deviate from acceptable standards of medical care and that its motion for summary judgment dismissing the complaint against it should be granted.
We do not believe that defendant made the requisite initial showing of entitlement to judgment as a matter of law in regard to plaintiff’s negligence claim. Defendant retained an independent duty to supervise plaintiff and prevent her from injuring herself, even after the attending physician’s instructions were given (see, Horton v Niagara Falls Mem. Med. Ctr., *76651 AD2d 152, 154-155, lv denied 39 NY2d 709). One of defendant’s own rules required any patient over the age of 65 years to have top side rails upon the bed during the night. Plaintiff swears that no side rails were placed upon her bed on the night in question in violation of this rule. It is generally accepted that plaintiff’s attending physician did not prescribe bed rails for plaintiff. However, the general rule that a hospital is not liable in negligence for the failure to erect bed rails absent professional direction does not apply where, as here, the hospital establishes a rule that bed rails are to be set up in all cases of patients over the age of 65 years, which this patient is (see, Haber v Cross County Hosp., 37 NY2d 888, 889).
Defendant’s failure to abide by its own rules is some evidence of negligence (see, supra, at 889; Danbois v New York Cent. R. R. Co., 12 NY2d 234, 239). Plaintiff’s sworn allegation that no bed rails were placed on her bed in violation of this rule raises at least a question of fact as to this issue and would impose liability upon defendant if the violation is found to be a proximate cause of plaintiff’s injury. If a violation of the rule is found by the jury to constitute negligence, such violation need not be the sole cause of plaintiff’s injury; it need only have been a substantial factor in bringing about the injury, i.e., a proximate cause as distinguished from the proximate cause (see, Galioto v Lakeside Hosp., 123 AD2d 421, 422). To establish a prima facie case based solely on circumstantial evidence, it is enough that plaintiff shows facts and conditions from which negligence of defendant and causation of the accident may reasonably be inferred (see, Schneider v Kings Highway Hosp. Ctr., 67 NY2d 743, 744).
Defendant argues that bed rails, even if properly placed, would not have prevented plaintiff from leaving the bed and that their purpose is solely to prevent plaintiff from falling out of bed and not from leaving the bed. This argument is but a self-serving declaration by defendant in support of its position in this law suit and should not be considered determinative of the negligence issue presented here. Defendant’s rule regarding bed side rails for patients over 65 years of age does not provide that their only purpose is to prevent a patient from falling out of bed. As a matter of proper protection in an action based on simple negligence when no expert testimony is necessary, a jury could properly decide as a matter of common knowledge that if bed rails had been properly placed in accordance with defendant’s own rule a person of plaintiff’s age and physical and mental condition would have been prevented or deterred from leaving her bed on her own, and *767that defendant’s failure to place side rails in these circumstances was a proximate cause of plaintiff’s fall (see, Coursen v New York Hosp.-Cornell Med. Ctr., 114 AD2d 254, 256). Accordingly, the order of Supreme Court should be modified by reversing that part of such order which dismissed the cause of action for negligence against defendant.
Weiss, P. J., and Yesawich Jr., J., concur.