[Pneumatization of the frontal sinus].

Through phylogeny and ontogeny, we follow the evolution of the frontal sinus; embryology gives details about the development of it. Then, we proceed to the investigation of factors influencing pneumatization. Afterwards, we analyse the different anomalies regarding pneumatization. In the last part, we mention experiments in progress being a link between cephalometry and the study of the frontal sinus surface in the diagnosis of skeletal Classes III.