A structured controlled vocabulary of stage-specific anatomical structures of the human. It has been designed to mesh with the mouse anatomy and incorporates each Carnegie stage of development (CS1-20). The timed version of the human developmental anatomy ontology gives all the tissues present at each Carnegie Stage (CS) of human development (1-20) linked by a part-of rule. Each term is mentioned only once so that the embryo at each stage can be seen as the simple sum of its parts. Users should note that tissues that are symmetric (e.g. eyes, ears, limbs) are only mentioned once.