1. SNOMED CT Diagramming notes
As shown diagrams must show descriptions and can optionally show identifiers.
Descriptions may be "Fully Specified Names" or "Preferred Terms" for diagram elements, but not a mixture of both on one diagram.
Shading maybe used with the colours shown in this template for each element type, or shading may be removed entirely for black and white diagrams.
Layout is generally left-to-right and top-to-bottom.
Relationships are ordered down the diagram as follows:
Is-a,
then ungrouped relationships,
followed by grouped relationships.
For finer grained ordering of relationships, the sort order defined in the Technical Implementation Guide should be used.
Elements and font size may be adjusted to suit needs, however where possible elements should remain rectangular, wider than they are tall.

2. SNOMED CT Diagramming without identifiers
Defined concept ≡
Defined concept
Attribute
Defined concept
Attribute
Defined concept
Attribute
Defined concept
Attribute
Concept

3. SNOMED CT Diagramming with identifiers
Defined concept ≡
Defined concept
Attribute
Defined concept
Attribute
Defined concept
Attribute
Defined concept
Attribute
Concept

4. SNOMED CT Expression subsumed by
Defined concept
Attribute
Defined concept ⊑
Concept
Attribute
Defined concept

5. SNOMED CT Expression subsumes
Defined concept
Attribute
Defined concept ⊒
Concept
Attribute
Defined concept

6. SNOMED CT Expression equivalent
Defined concept
Attribute
Defined concept ≡
Concept
Attribute
Defined concept