Common-knowledge exception refers to a legal principle exempting testimony concerning simple medical procedures in a medical mal practice action. Common-knowledge exception is considered a narrow exception. Under the common-knowledge exception, a medical malpractice plaintiff is required to present an expert testimony in order to establish negligence. The common-knowledge exception is also the basis for res ipsa loquitur theory of negligence.In Fossett v. Bd. of Regents, 258 Neb. 703 (Neb. 2000), it was held that common-knowledge exception is an exception to the requirement of expert testimony. It is invoked in a situation where the evidence and the circumstances are such that the recognition of the alleged negligence may be presumed to be within the comprehension of laymen.