Location of alveolar clefts relative to the incisive fissure.

OBJECTIVE The purpose of this study was to investigate, in a normal human fetal sample, the development of the anterior area of the palate. Emphasis has been placed on the bilateral epithelial fusion lines between the soft-tissue palatal shelves and the premaxillary mucosa, and on the relationship between these fusion lines and the locations of the inclusive fissures and of the tooth buds. The goal was to evaluate how the location of clefts in cleft lip and palate (CLP) patients interferes with tooth buds that are often affected in clefting. DESIGN Nineteen maxillas of human fetuses underwent histologic examination after serial horizontal sectioning. Superimpositions of tracings from photographs of the histologic sections yielded information on the maxillary morphology at different levels. RESULTS After elevation and fusion of the soft-tissue palatal shelves, the palatal fusions were Y-shaped. During subsequent osseous palate development, including formation of the incisive fissure and intermaxillary suture, the Y-shaped epithelial fusions disintegrated. The locations of the anterior arms of the epithelial Y and of the incisive fissure did not coincide. CONCLUSIONS The incisive fissure is likely not the location of clefts in CLP. The location of anterior palatal clefting in CLP patients follows the original course of the epithelial fusion between the palatal shelves and the premaxillary mucosa found in the region of the lateral incisors.