Clinical and pathologic features of maxillonasal dysplasia (Binder's syndrome): significance of the prenasal fossa on etiology.

Clinical and pathologic anatomic parameters were studied in 50 patients with maxillonasal dysplasia (Binder's syndrome). The skeletal deformity causing the flat and low-set nose was in typical patients a palpable depression in the anterior nasal floor (fossa prenasalis) and a localized maxillary hypoplasia in the alar base region. Class III malocclusion was found in 54 percent. In 6 percent of the patients a slope (sulcus prenasalis) was found instead of a fossa in the anterior nasal floor, and in one patient a rudimentary fossa was found. Concomitant malformations were noted in 18 percent, and a hereditary connection was seen in 16 percent. The etiology is discussed in relation to the development of the premaxilla and the appearance of a secondary external trabecular network of bone in the canine region. An inhibition of the latter ossification center would explain the localized hypoplasia in the floor and walls of the piriform aperture in maxillonasal dysplasia.