The Foundational Model of Anatomy ontology has four interrelated components:

1. Anatomy taxonomy (At),
classifies anatomical entities according to the characteristics they share (genus) and by which they can be distinguished from one another (differentia)
-designated in previous publications as the Anatomy ontology or Ao;

2. Anatomical Structural Abstraction (ASA),
specifies the part-whole and spatial relationships that exist between the entities represented in At;

3. Anatomical Transformation Abstraction (ATA),
specifies the morphological transformation of the entities represented in At during prenatal development and the postnatal life cycle;

4. Metaknowledge (Mk),
specifies the principles, rules and definitions according to which classes and relationships in the other three components of FMA are represented.

Thus, the Foundational Model of Anatomy ontology may be represented by the abstraction:

FMA = (At, ASA, ATA, Mk)