Figure 2: Histogram of the sinus depth.
From: Morphometric analysis of sinus depth in the posterior maxilla and proposal of a novel classification
Vertical lines resemble the first and the third quartile used as class limits. The first quartile was 0 mm and the third quartile 6 mm. The first class has a sinus floor above the hard palate, the second class’ floor is 0 to 6 mm below and the third class is more than 6 mm below the hard palate. The first class resembles 25%, the second class 50% and the third class 25% of the patients.
