This viewpoint traces the citizen-centred ontology of the MyHealth@MyHands across four architectural layers (legal and policy), Citizen Ontology (business layer), Organisational Actors, Semantic Layer (data standards), and Technical Layer (implementation components). The diagram is structured around five traceability chains, each anchored to a core citizen concept . Patient Identity, Health Journey, Care Pathway, Service Event and Dataset. each chain reads left to right, showing how a citizen-level concept is grounded in a legal or policy obligation, governed by an organisational actor, expressed through a semantic or data standard, and ultimately realised by a technical component within the platform . This viewpoint is not exhaustive. It represents the primary traceability paths for the core citizen concepts within the current scope. As the project develops through additional use cases, extended regulatory requirements, or broader Member State integration , further chains and elements can be incorporated to the viewpoint model.