Abstract: A medical knife assembly includes an outer clamp assembly and an inner clamp blade assembly having a cutting blade assembly. The inner and outer clamp assemblies are pivotally connected at about their proximate ends so they may be squeezed together with one hand to affect a novel method of clamping and cutting in a single motion operation. A set of shear pins holds the component parts of the inner and outer assemblies together in a ready position that enables a user to properly position the knife assembly for severing an umbilical cord at the time of birth. Once the umbilical cord is severed, the component parts of the inner and outer assemblies separate providing independent clamps, one staying with an infant segment of the umbilical cord and one staying with a maternal segment of the umbilical cord.