---
type: "datatype"
title: "Element"
datatype: "Element"
---
# Element

- [Datatypes](/datatypes)
- [Definitions](/datatypes-definitions#Element)
- [Examples](/datatypes-examples#Element)
- [Mappings](/datatypes-mappings#Element)
- [Profiles](/datatypes-profiles#Element)

## Elements

- **[Element.@id](/datatypes-definitions#Element.%40id)** [0..1]: [string](/string) Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces
- **[Element.extension](/datatypes-definitions#Element.extension)** [0..*]: [Extension](/Extension) May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and managable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension

## Aliases

- **Element.extension**: extensions, user content

## Comments

- **Element.extension**: There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone

## Mappings

- **Element.@id**: RIM Mapping: n/a
- **Element.extension**: RIM Mapping: n/a