The psychosomatic family model of Minuchin and his colleagues is one of the best known and influential viewpoints in the field of family therapy. This article critically analyses this model and related concepts, focusing on the lack of clear definitions, especially with regard to the interactional concepts: enmeshment, rigidity, overprotectiveness, and lack of conflict resolution. Each concept is discussed, concluding with the recommendation of a new definition, so that the model can be empirically verified. The authors suggest that Minuchin's model can be reduced to three fundamental interactional dimensions: the intensity of intrafamilial boundaries, the degree of the family's adaptability, and the family's way of handling conflicts. A research method is presented in which the way of assessing these interactional dimensions is demonstrated.