Much of the airflow through the nose occurs through the narrow space between the septum and the inferior turbinate A common cause of nasal airway obstruction is called a nasal septal deviation. This is a view of the nasal passage with the external nose removed. The septum can narrow this space on one side if it is deviated to that side. A ridge of bone that can often narrow the opposite side is seen.
The nasal septum divides the nasal cavity into two symmetric parts. A departure of the septum from the midline (deviation) causes an alteration of the normal nasal function. This deviation can produce different symptoms depending in its location and size.
The septum, with the other nasal structures, helps to control the airflow, promoting some turbulence inside the nose, to facilitate the nasal function. The turbulence helps to humidify, clean and heat (or cool) the inspired air. When the septum is not straight, changes in the dynamics of the airflow can produce different symptoms. Most common is nasal obstruction. This is especially true in the case of deviation in the first two centimeters of the nose beginning in the nasal valve. This is the area which contributes the most to nasal resistance (Haight and Cole, 1982). This is the reason why small deviations in an anterior position causes more symptomatology than large deviations in posterior locations. The same alteration in the airflow can cause drying of the mucosa in areas excessively exposed to the airflow. This produces crusting, and in some patients bleeding when the crust is removed.
Frequency of congenital septum deviation has been reported to be from 4% to 5% (Podoshin, 1991 and Cottle, 1958 , respectively)
A wide range of frequencies has been described for congenital septal deviation. From 0.93% in Israel (Podoshin, 1991 ), to 14.3% in Poland (Soboczynski, 1992 ). In Finland, septal deviation as a clinical diagnosis was found in 9.5% of school children (Haapaniemi, 1995 ).
Nasal obstruction is the most common complain of septal deviation, although not all patients with septal deviation are symptomatic. Nasal deformity can be found in many patients. Other symptoms related in adults are: snoring (57.3%), headache (48.0%), rhinorrhoea (38.7%), sneezing (30.7%), hyposmia (30.7%) and epistaxis (21.3%) (Low, 1992 ).
The diagnosis requires rhinoscopy before and after decongestion of the mucosa with local vasoconstrictors like oximetazoline. Endoscopic examination of the nose provides good information of the posterior part of the nose, and is useful to visualize the valvular area. Is common to find, contralateral to the deviation, hypertrophy of the inferior turbinate. This hypertrophy compensates the decrease of resistance in that side of the nose, due to the increase of space.
Subluxation refers to the displacement of the septal cartilage most commonly from its articulation with the vomer. This usually results in a horizontal spur which, depending on its size can obstruct the airflow, make contact with the inferior turbinate in its side or be impacted in it.
Spurs are projections from the septum. The size can vary, but most commonly they are found in the condrovomeral area. More important than size is the amount of obstruction they produce, or structures they affect. Some spurs can reach the lateral wall of the nose and impact in it. This frequently happens in the posterior part of the nose.
Caudal deflections are deviation in the most anterior part of the nose. These deviations can obstruct the nasal valve due to its location. They are commonly accompanied by an anterior subluxation that continues towards the posterior part of the nose, over the articulation of cartilage and vomer.
Tension septum is a term developed by Cottle, to describe a special condition in which the vertical height of the septum is too large, producing a tall, large and narrow nose. The mucosa covering the septum is "under tension", being too short for it. This is somewhat debatable, but the condition is found with some frequency.
The inferior turbinates tend to grow to fill the available space. Long standing septal deviations can cause the inferior turbinate to enlarge on the concave side of the deviation. Often, the concave side of the deviation seems more obstructed to the patient. This may be from an enlarged turbinate or from turbulent airflow on this side. Several methods are available to reduce the size of enlarged turbinates and increase the available breathing space.