It is an effective orthopedic procedure, which consists in the separation of the two hemiarchs of the maxilla, by means of the mid palatal suture, through forces produced by the hyrax type disjunctor. This device is the most used in the orthodontic field due to the results obtained when activated, thus solving transversal problems, maxillary atresia, dental crowding and mouth breathing patients.Nowadays many studies mention that by having an enlargement of the nasal cavity there is a better breathing in patients with this type of nature.That is why the importance of this research is to know what are the effects that are produced when performing a rapid expansion of the maxilla at dental, skeletal, facial and cephalometric level.