The nasal valve and current technology

The principal features and the respiratory role of the nasal valve are surveyed briefly and contributions of current computer-aided techniques of imaging, rhinomanometry, and acoustic rhinometry to an understanding of its structure and function are presented. The nasal valve is a dynamic segment of the anterior nasal airway, where the major portion of nasal resistance is localized and nasal resistance to respiratory airflow approximates half the airflow resistance of the entire respiratory system. This functioning valvular segment of the airway extends several mm beyond its triangular entrance in the compliant vestibule to the hemi-piriform entrance of the rigid cavum. Alar muscles assist in stabilizing the compliant lateral wall of the valve by resisting transmural pressures generated by inspiratory airflow and by adjustment of alar positioning, these muscles can also direct the inspiratory air stream (e.g., olfactory sniffs). Abundant erectile tissues of both medial and lateral nasal walls are prominent in the valve region, and they play the governing role in regulation of valve lumen and consequent nasal airflow resistance. Pathological mucosal swelling is the commonest cause of obstructive nasal disease, and the narrowed site of the valve is so vulnerable to obstruction that recurring physiological mucovascular swellings frequently impede airflow in the presence of small anterior structural deviations. Assessment of obstructive nasal disease by symptomatology is unreliable, and rhinoscopy has substantial limitations; however, current technology provides minimally invasive, objective, and reliable methods for the study of nasal patency and for the acquisition of useful and dependable clinical information.