This article aims to explore the psychological changes that arise during the process of becoming an adolescent. During this period, the family plays an important role in the (re)construction of the adolescent's internal world, being an extended mental space which may include the expression of dreams, phantasies, and desires. The concept of the “field”, as developed by Ferro (2007/2011), is used in order to be able to understand the adolescent's ongoing changes; these changes are very evident in his/her physical body, and the adolescent now has new object(s) with new aims that are enrolled in a family's dynamics. The clinical setting offers a privileged space in which to reveal changes present during this period of growth. Accordingly, we illustrate the value of applying the concept of the field to the process of adolescent growth by describing a clinical situation in which ideas about body and family are seen in dynamic interaction and in a relationship of intersubjectivity and co-construction.