The present invention provides an easily transportable immobilization device and system designed to immobilize fractures, severe sprains or soft tissue injuries within a body structure. The device generally contains a shaped body having one or more portions constructed and arranged to fit onto a leg or arm having a fracture, severe strain or soft tissue injury. The device utilizes a multilayer construction which allows for the delivery of the device to an individual in need in a compressed state. Activation allows a portion of the device to return to the non-compressed state, uniformly expanding outwardly, both longitudinally and radially. As the device expands, it surrounds and contacts the injured body structure, thereby applying a pressure as well as preventing lateral movement. The injured body structure is completely immobilized and secured until proper evaluation and care can be performed.