Nasal development occurs during weeks 4 through 10 of gestation and begins when migrating neural crest cells populate the frontonasal prominence and form the nasal placodes. These placodes appear as convex thickenings on the surface ectoderm of the frontonasal prominence and later form the olfactory epithelium. By the fifth week, a central depression appears in the placodes to form the primitive nasal pit. The nasal pit separates the lateral nasal prominence on the outer edge from the medial nasal prominence on the inner aspect. Mesenchymal proliferation around the nasal placodes allows these horseshoe-shaped prominences to fuse with the maxillary process to form the anterior nares. The depression separating the maxillary prominence from the lateral nasal prominence is known as the nasolacrimal groove, and eventually gives rise to the nasolacrimal duct. The nasal pits grow toward the oral cavity and develop into the early nasal fossae. The bucconasal membrane separates the nasal cavities from the oral cavity. This membrane subsequently disappears, allowing for communication of the nasal cavities with the oral cavity, forming the primitive posterior nasal choanae. The medial nasal prominence gives rise to part of the nasal septum and the medial crus of the lower lateral alar cartilage. The lateral nasal prominence develops into the external wall of the nose, nasal bones, upper lateral cartilage, alae, and lateral crus of the lower lateral cartilage. The frontonasal process lies in the midline and is the precursor to the nasal septum and palate (Figure 11–1).
Diagram of embryologic development of the nose.
Losee et al (2004) developed a comprehensive classification for congenital nasal deformities and divided them into 4 categories. Type I deformities include hypoplasia and atrophy (paucity of tissue), type II are hyperplasia and duplications (excess of tissue), type III are clefts, and type IV deformities consist of neoplasms and vascular anomalies (both benign and malignant).
M. Congenital nasal obstruction: clinical and radiologic review. Eur J Pediatr.
. (The article discusses the embryology of the nasal passage and subsequent causes of nasal obstruction.)
RR. Nasal, septal, and turbinate anatomy and embryology. Otolaryngol Clin North Am.
. (The article describes development and anatomy of nasal structures.)
JS. Congenital nasal malformations. Otolaryngol Clin North Am.
. (The article discusses embryology and development of congenital nasal abnormalities.)
et al. Congenital nasal anomalies: a classification scheme. Plast Reconstr Surg.
. (The article proposes a classification of congenital nasal deformities.)
Arrhinia is the congenital partial or complete absence of the nose and ...