Table 4.

Relationship between frontal sinus width and forehead protrusion of all samples

Index	Number	Mean ± SD (cm)		P
		frontal sinus width	forehead protrusion
All samples	405	0.841 ± 0.269	0.975 ± 0.192	0.002*
Sex
Male	204	0.937 ± 0.291	0.995 ± 0.211	0.013*
Female	201	0.743 ± 0.204	0.956 ± 0.170	0.587
Age
Adult	152	0.880 ± 0.301	1.033 ± 0.189	<0.001**
Teenager	160	0.848 ± 0.250	0.983 ± 0.181	0.660
Child	93	0.766 ± 0.230	0.868 ± 0.172	0.968
Dentoskeletal classification
Class I	204	0.849 ± 0.287	1.002 ± 0.194	0.009*
Class II	127	0.820 ± 0.233	0.977 ± 0.185	0.118
Class III	74	0.855 ± 0.277	0.899 ± 0.180	0.320
Forehead’s most convex part
In the upper 1/3	14	0.757 ± 0.248	1.019 ± 0.262	0.930
In the middle 1/3	187	0.764 ± 0.217	0.974 ± 0.173	0.179
In the lower 1/3	204	0.917 ± 0.293	0.974 ± 0.204	0.002*

The Number in all categories refers to cases in which the maximum anterior-posterior diameter of the frontal sinus can be traced and measured in the lateral cephalometric radiograph

*Statistical significance (P < 0.05) as determined by Pearson’s two-variable analysis

**Highly statistically significant (P < 0.001)