Introduction: The etiology of the hypoplasia of the maxillary sinus is unknown, some authors believe that the hypothesis of the obstruction of the ostiomeatal complex would hinder the drainage of the sinus and would promote a negative pressure. Chronically, the negative pressure would be responsible for the collapse of the paranasal sinus and for morphologic alterations, could result in conditions as enophthalmos and hypoglobus. Many authors use the term syndrome of the silent sinus to describe the same entity, however, in different phase of evolution, diagnosed by computed tomography (CT) scan of the sinus.