Table 4.

The classification of the outline of the upper border of the frontal sinus among the Indian population

Outline of upper border	Number of sample (%)		Class number
	Left	Right
Absent	13 (3.5)	4 (1.1)	00
Scalloped with 1 arcade	91 (24.7)	83 (22.6)	1
Scalloped with 2 arcades	124 (33.7)	114 (31)	2
Scalloped with 3 arcades	84 (22.83)	116 (31.5)	3
Scalloped with 4 arcades	40 (10.9)	36 (9.8)	4
Scalloped with 5 arcades	10 (2.72)	9 (2.4)	5
Scalloped with 6 arcades	4 (1.1)	2 (0.5)	6
Scalloped with 7 arcades	2 (0.55)	4 (1.1)	7