Unified Medical Language System® (UMLS®) Basics

Parent - Child (broader/narrower) Relationships

One of the more important relationships within the Semantic Network is the Parent-Child, or Broader-Narrower, relationship. This relationship illustrates the hierarchies that exist between biomedical concepts. Child (narrower) relationships can be thought of as a ‘subtype.’ For example, the semantic type Biologic Function is the parent of, or broader than, the semantic type Physiologic Function.

It is important to note that the level of granularity varies across the Network. For example, a child of Physical Object is Manufactured Object. Manufactured Object has only two child terms, Medical Device and Research Device. It is clear that there are manufactured objects other than medical devices and research devices. Rather than expand the number of semantic types, concepts that are neither medical devices nor research devices are simply assigned the broader semantic type Manufactured Object.

Some examples of the Parent-Child Relationship: