Parts and Wholes

Part-whole relations (or partonomies) play a critical role in medical concept representation. This is most obvious in the modelling of anatomy but it also affects the representation of surgical procedures – which usually act on anatomy – as well as many physiological or disease processes. Part-whole relations have long been the subject of extensive study both in the linguistic and knowledge representation communities.

The GRAIL description logic formalism and the issues in its design are described in detail in the GRAIL Tutorial. Certain features of the formalism are specifically relevant to representing part-whole relations. These are summarised here:

• Semantic links (attributes) can be declared as transitive, e.g. to represent formally that parts of parts of a whole are parts of the whole.
• One semantic link can be declared to be inherited along another (refinement), e.g. to state that a disease involving a structure that is a part-of a whole is a kind of disease involving the whole.
• Semantic links as well as concepts may be organised into an is-kind-of (subsumption) hierarchy, e.g. to say that the link component-of is a kind of the link part-of, with the interpretation that a component-of something is de facto also a kind of a part-of that thing.

For historical reasons, the names of the OpenGALEN links are potentially confusing. Below are the OpenGALEN partonomic links as an expanded tree structure, the names used in the remainder are in italics between brackets.

• InversePartitiveAttribute (part-of)
  • InverseStructuralPartitiveAttribute
    • IsDivisionOf (structure-part-of)
      • isArbitraryComponentOf (arbitrary-part-of)
      • isLinearDivisionOf (segment-of)
      • isSolidRegionOf (solid-piece-of)
        • isBlindPouchDivisionOf (pouch-of)
        • isLayerOf (layer-of)
        • isSolidDivisionOf (irregular-piece-of)
      • isStructuralComponentOf (component-of)
        • isFunctionalComponentOf (func-component-of)
        • isPartitiveConnectionOf
        • isPartitivelyContainedIn
          • isMixedThroughout (portion-of)
            • isDissolvedWithin (dissolved-in)
            • isInSuspensionWithin (suspended-in)
      • isSurfaceDivisionOf (surface-of)
    • makesUp (stuff-of)
  • InverseProcessPartitiveAttribute
    • IsSubprocessOf (subprocess-of)