Final answer:
The method in which the client's head is kept outside during a full body steam bath is called a partial steam bath. It provides various health benefits without exposing the head to excessive heat.
Step-by-step explanation:
The method of a full body steam bath where the client's head is kept outside the cabinet or tent is known as a partial steam bath. This form of steam therapy is designed to envelop the body in warm, moist heat while allowing the head to remain cool. It is believed to provide various health benefits like improving circulation, reducing stress, and aiding in detoxification, all while avoiding excessive heat to the head which can be uncomfortable for some individuals.