Isolation of mouse embryos 1. Sacrifice impregnated mouse. 2. Dissect out the uterus of the mouse. Pulling up on the uterus with one set of forceps, use another to tear the mesometrium away from the uterus. Click here for large version of movie 3. Remove the embryos from the uterus. Separate them into one or two embryo fragments. 4. Using fine forceps, separate the muscular wall of the uterus, Reichert's membrane and visceral yolk sac from the actual embryo. Click here for embryo isolation movie