The medial nasal processes remain separated through the medial parts of the frontonasal process. Mesenchyme grows from the medial nasal processes into the roof of the oral depression. The medial and the lateral nasal processes as well as the maxillary process come into contact with each other at the outer part of the floor of the nasal pit; they eventually fuse together. Within the nasal pit, only the medial and the lateral nasal processes fuse together (animation: facial development stage 13-15).