Unified Medical Language System® (UMLS®) Basics

Identifiers in the Semantic Network

The information associated with each semantic type includes:

• A unique identifier
• A tree number indicating its position in the `isa' hierarchy
• A definition
• Its immediate parent and children

The information associated with each relationship includes:

• A unique identifier
• The semantic type
• A tree number
• A definition
• Examples
• The set of semantic types that can plausibly be linked by this relationship.

example Semantic Network record:

STY|T020|Acquired Abnormality|A1 . 2 . 2 . 2|An abnormal structure, or one that is abnormal in size or location, found in or deriving from a previously normal structure . Acquired abnormalities are distinguished from diseases even though they may result in pathological functioning (e . g . , "hernias incarcerate") . |Abscess of prostate; Hemorrhoids; Hernia, Femoral; Varicose Veins||||| Acquired Abnormality|co-occurs_with|Injury or Poisoning|D| Acquired Abnormality|isa|Anatomical Abnormality|D| Acquired Abnormality|result_of|Behavior|D|