| Source Element | Usage | Target |
| Requirements | UseExtension | http://hl7.org/fhir/5.0/StructureDefinition/extension-Requirements |
| Requirements.id | UseExtensionFromAncestor | - |
| Requirements.meta | UseExtensionFromAncestor | - |
| Requirements.implicitRules | UseExtensionFromAncestor | - |
| Requirements.language | UseExtensionFromAncestor | - |
| Requirements.text | UseExtensionFromAncestor | - |
| Requirements.contained | UseExtensionFromAncestor | - |
| Requirements.extension | UseExtensionFromAncestor | - |
| Requirements.modifierExtension | UseExtensionFromAncestor | - |
| Requirements.url | UseExtensionFromAncestor | - |
| Requirements.identifier | UseExtensionFromAncestor | - |
| Requirements.version | UseExtensionFromAncestor | - |
| Requirements.versionAlgorithm[x] | UseExtensionFromAncestor | - |
| Requirements.name | UseExtensionFromAncestor | - |
| Requirements.title | UseExtensionFromAncestor | - |
| Requirements.status | UseExtensionFromAncestor | - |
| Requirements.experimental | UseExtensionFromAncestor | - |
| Requirements.date | UseExtensionFromAncestor | - |
| Requirements.publisher | UseExtensionFromAncestor | - |
| Requirements.contact | UseExtensionFromAncestor | - |
| Requirements.description | UseExtensionFromAncestor | - |
| Requirements.useContext | UseExtensionFromAncestor | - |
| Requirements.jurisdiction | UseExtensionFromAncestor | - |
| Requirements.purpose | UseExtensionFromAncestor | - |
| Requirements.copyright | UseExtensionFromAncestor | - |
| Requirements.copyrightLabel | UseExtensionFromAncestor | - |
| Requirements.derivedFrom | UseExtensionFromAncestor | - |
| Requirements.reference | UseExtensionFromAncestor | - |
| Requirements.actor | UseExtensionFromAncestor | - |
| Requirements.statement | UseExtensionFromAncestor | - |
| Requirements.statement.id | UseExtensionFromAncestor | - |
| Requirements.statement.extension | UseExtensionFromAncestor | - |
| Requirements.statement.modifierExtension | UseExtensionFromAncestor | - |
| Requirements.statement.key | UseExtensionFromAncestor | - |
| Requirements.statement.label | UseExtensionFromAncestor | - |
| Requirements.statement.conformance | UseExtensionFromAncestor | - |
| Requirements.statement.conditionality | UseExtensionFromAncestor | - |
| Requirements.statement.requirement | UseExtensionFromAncestor | - |
| Requirements.statement.derivedFrom | UseExtensionFromAncestor | - |
| Requirements.statement.parent | UseExtensionFromAncestor | - |
| Requirements.statement.satisfiedBy | UseExtensionFromAncestor | - |
| Requirements.statement.reference | UseExtensionFromAncestor | - |
| Requirements.statement.source | UseExtensionFromAncestor | - |