Anatomy & Cell Biology

Table 8

Distribution of frontal sinus patterns between age groups

Age groupsa)	Frontal sinus presence				Frontal sinus absence				Grand total
	Symmetry	Asymmetry		Total	Bilateral absence	Unilateral absence		Total
	Symmetry	Right dominant	Left dominant	Total	Bilateral absence	Right absence	Left absence	Total
Group I (n=82)	33 (40.2)	16 (19.5)	29 (35.4)	78 (95.1)	3 (3.7)	0	1 (1.2)	4 (4.9)	82 (100)
Group II (n=79)	32 (40.5)	15 (19.0)	31 (39.2)	78 (98.7)	1 (1.3)	0	0	1 (1.3)	79 (100)
Group III (n=83)	37 (44.6)	12 (14.5)	29 (34.9)	78 (94.0)	2 (2.4)	3 (3.6)	0	5 (6.0)	83 (100)
Group IV (n=82)	34 (41.5)	14 (17.1)	30 (36.6)	78 (95.1)	1 (1.2)	2 (2.4)	1 (1.2)	4 (4.9)	82 (100)
Group V (n=83)	31 (37.3)	19 (22.9)	28 (33.7)	78 (94.0)	4 (4.8)	1 (1.2)	0	5 (6.0)	83 (100)
Total	167 (40.8)	76 (18.5)	147 (36.0)	390 (95.4)	11 (2.7)	6 (1.5)	2 (0.5)	19 (4.6)	409 (100)

Values are presented as number (%). ^a)Aage range: group I, 20–29 yr; group II, 30–39 yr; group III, 40–49 yr; group IV, 50–59 yr; group V, 60–69 yr.