How do I know that I have a case of split abdomen muscles?

To check for diastasis recti, 4–7 days after delivery, lie on your back with your knees bent and feet flat on the floor. Tuck your chin towards your chest, and slowly lift your head (and shoulders slightly), pressing your lower back into the floor. Now, place your fingertips in the middle of your abdomen just above your belly-button. If you feel a soft pulpy gap between the muscles of more than two fingers’ width, then you probably have split recti muscles.