Rapid Maxillary expansion or palatal expansion as it is sometimes called, occupies unique niche in dentofacial therapy. Rapid Maxillary expansion (RME) is a skeletal type of expansion that involves the separation of the mid-palatal suture and movement of the maxillary shelves away from each other. RME effects the maxillary complex, palatal vaults, maxillary anterior and posterior teeth, adjacent periodontal structures to bring about an expansion in the maxillary arch. Morphogenesis and anatomical features of the upper jaw determine the choice of the method of rapid palatal expansion with narrowing of the upper dentition, as an effective method for eliminating congenital deformities of the maxillofacial region. The majority of dental transverse measurements changed significantly as a result of RME. The maturity of the maxillofacial structures determines the timing and degree of success of rapid palatal dilatation treatment.