Anatomical dead space is equivalent to:

Anatomic dead space refers to the volume of the conducting airways and is around 130 - 180ml (2ml/kg throughout life) in the adult i.e about 1/3rd of tidal volume. Physiologic dead space: It refers to the propoion of the tidal volume that does not paicipate directly in gas exchange. It consists of the anatomic dead space and the alveolar dead space. It comprises 25 - 35% of of the normal tidal volume.