The author discusses the claustrum as an aspect of pathological containment within inner space and its relation to Bion's (1962a, b) container-contained concept. Having outlined the early psychoanalytic conceptual foundations of claustrophobia and the claustrum, the author charts the term from its introduction by Erikson in 1937 through its divergent developmental trajectories within the conceptual vocabulary of the classical, Independent and Kleinian schools up to Meltzer's (1992) contemporary reworking. The vicissitudes of the transmission of ideas within and between these groups is stressed, Esther Bick's work being particularly highlighted as an example of a nodal intellectual influence. The claustral space within the physical or internal object body, its internal structuralization, and the impairments in quality of psychic life of the selves that seek to inhabit such spaces, entered through intrusive projective identification, are highlighted. Developmental and psychopathological claustrum manifestations are discussed, particularly fear, separation, problems mourning and claustrophobia. A reciprocal and hierarchical avatar relation between the claustrum and the container is proposed.