What is the difference between regional anesthesia, epidural anesthesia and nervous blocks?

Regional anesthesia. Regional: a general term for nerve blocks of the extremities head and torso. An epidural is a type of regional anesthesia that is used for numbing the lower body from the umbilicus down. A nerve block is a specific nerve(or nerves being numbed. An interscalene nerve block is used to numb one arm for example. But an ISB is a type of regional anesthesia.