Measurement of the lengths of different sections of the upper airway and their predictive factors

No studies have been conducted to define the lengths of the upper airway’s different segments in normal healthy adults.

This study aimed to determine the length of the subglottis and extrathoracic trachea and the factors affecting it.

This was an observational retrospective review study. Included 102 adult patients who underwent CT scan during the quiet inspiration phase of the upper airway.

The results revealed significant positive linear relationships between height and both anterior and posterior subglottic measurements (p < 0.001). Additionally, a statistically significant, moderately strong negative correlation between age and extrathoracic tracheal measurements (p > 0.001) was observed. Men exhibited longer anterior (p < 0.001) and posterior (p > 0.001) subglottic measurements. In both sexes, the average length of the anterior subglottis was 14.16 (standard deviation [SD]: 2.72) mm, posterior subglottis was 14.51 (SD: 2.85) mm and extrathoracic trachea was 66.37 (SD: 13.71) mm.

We concluded that a normal healthy adult’s anterior subglottis length is 6.3–19.3 mm (mean: 14.16 [SD: 2.72] mm), posterior subglottis length is 6.1–20.0 mm (mean: 14.51 [SD: 2.85] mm) and extrathoracic trachea length is 25.2–98.5 mm (mean: 66.37 [SD: 13.71] mm). Age, height and sex affected the upper airway length.