Abstract: An orthopedic heating or cooling system to be built into a cast or splint and bodily integrated with it as the cast is being applied to the patient. One or more individual units are used independently or in combination to form a flowing liquid system to heat or cool specific portions of the injured limb in a controlled fashion. The individual units include liquid carrying tubes held in a fixed, crossing pattern and integrated into the cast by means of an open mesh covering. Hot or cold fluid is pumped from a reservoir through one or more of the individual units in the desired sequence and amount and then expelled back into the temperature controlled or conditioned reservoir. In this fashion one may heat or cool the entire area under the cast or only specific sections, as desired, greatly increasing the comfort to the patient.