Auricular dimensions in computed-tomography: Unveiling the relationship between ear dimensions, age, and sex using three-dimensional volume rendering reconstructions

Table 1 Standardization for auricular size assessment using predefined anatomical landmarks

Measurement	Definition
Length 1	Distance between sa and sba in cm
Length 2	Distance between t and sba in cm
Width 1	Distance between pa and base sup (at the vertical level from pra sup) while distance line needs to be orthogonal to length1 in cm
Width 2	Distance between t and pa in cm
Perimeter	Auricular perimeter measured through distance lines including sa, pa, sba, pra inf, t and pra sup in cm

sa: Superaurale; sba: Subaurale; t: Tragion; pa: Postaurale; sup: Superior; inf: Inferior; pra: Preaurale

Table 2 Quantitative results for size measurements in cm for males (n = 329) in total and for each age group, mean ± SD/ 95%CI

Side	Measurement (cm)	Total	18-30 year (n = 35)	31-50 year (n = 63)	51-70 year (n = 140)	71-90 year (n = 83)	> 91 year (n = 8)
Right ear	Length 1	6.91 ± 0.51	6.44 ± 0.34	6.66 ± 0.48	6.97 ± 0.46	7.17 ± 0.43	7.29 ± 0.5
		6.47-7.36	6.17-6.71	6.28-7.04	6.61-7.34	6.82-7.51	6.93-7.66
	Length 2	2.83 ± 0.35	2.51 ± 0.23	2.73 ± 0.34	2.84 ± 0.32	3 ± 0.31	3.09 ± 0.29
		2.44-3.22	2.19-2.83	2.26-3.21	2.4-3.29	2.57-3.42	2.76-3.42
	Width 1	3.94 ± 0.32	3.36 ± 0.2	3.86 ± 0.29	3.98 ± 0.3	4.06 ± 0.31	4.19 ± 0.39
		3.58-4.31	3.40-3.86	3.54-4.18	3.37-4.32	3.76-4.36	3.81-4.57
	Width 2	3.51 ± 0.34	3.34 ± 0.27	3.4 ± 0.26	3.51 ± 0.32	3.66 ± 0.35	3.76 ± 0.44
		3.14-3.89	3.03-3.65	3.11-3.69	3.15-3.87	3.26-4.05	3.26-4.25
	Perimeter	17.66 ± 1.25	16.36 ± 0.78	17.11 ± 1.13	17.81 ± 1.1	18.26 ± 1.11	18.7 ± 1.48
		17.05-18.27	15.98-16.74	16.54-17.68	17.27-18.35	17.71-18.8	18.02-19.39
Left ear	Length 1	6.93 ± 0.52	6.46 ± 0.37	6.7 ± 0.5	6.98 ± 0.48	7.19 ± 0.46	7.29 ± 0.56
		6.47-7.39	6.17-6.76	6.3-7.1	6.59-7.36	6.82-7.55	6.87-7.71
	Length 2	2.84 ± 0.34	2.54 ± 0.23	2.76 ± 0.35	2.85 ± 0.31	2.97 ± 0.32	3.1 ± 0.32
		2.45-3.22	2.22-2.86	2.27-3.24	2.43-3.28	2.54-3.41	2.73-3.46
	Width 1	4.01 ± 0.36	3.69 ± 0.25	3.91 ± 0.32	4.05 ± 0.33	4.13 ± 0.35	4.4 ± 0.38
		3.61-4.42	3.41-3.97	3.55-4.27	3.68-4.42	3.78-4.48	4.03-4.78
	Width 2	3.46 ± 0.31	3.32 ± 0.24	3.36 ± 0.24	3.47 ± 0.32	3.57 ± 0.33	3.72 ± 0.32
		3.11-3.82	3.05-3.6	3.09-3.64	3.11-3.835	3.2-3.94	3.35-4.08
	Perimeter	17.71 ± 1.28	16.47 ± 0.82	17.21 ± 1.16	17.84 ± 1.21	18.29 ± 1.12	18.76 ± 1.38
		17.1-18.32	16.07-16.87	16.62-17.79	17.25-18.44	17.74-18.84	18.12-19.39

Table 3 Quantitative results for size measurements in cm for females (n = 342) in total and for each age group, mean ± SD/ 95%CI

Side	Measurement (cm)	Total	18-30 year (n = 18)	31-50 year (n = 85)	51-70 year (n = 101)	71-90 year (n = 122)	> 91 year (n = 16)
Right ear	Length 1	6.44 ± 0.5	6.03 ± 0.34	6.15 ± 0.43	6.43 ± 0.43	6.66 ± 0.44	6.93 ± 0.51
		6.05-6.84	5.74-6.33	5.77-6.52	6.09-6.78	6.3-7.01	6.56-7.31
	Length 2	2.7 ± 0.32	2.43 ± 0.2	2.53 ± 0.26	2.67 ± 0.27	2.84 ± 0.32	3.05 ± 0.26
		2.26-3.15	2.15-2.71	2.18-2.89	2.3-3.04	2.48-3.2	2.76-3.35
	Width 1	3.6 ± 0.32	3.44 ± 0.18	3.39 ± 0.26	3.63 ± 0.34	3.72 ± 0.27	3.79 ± 0.29
		3.24-3.96	3.23-3.64	3.09-3.68	3.25-4.01	3.42-4.02	3.5-4.07
	Width 2	3.3 ± 0.3	3.12 ± 0.2	3.14 ± 0.26	3.28 ± 0.25	3.44 ± 0.29	3.47 ± 0.43
		2.96-3.65	2.85-3.4	2.85-3.43	2.94-3.63	3.1-3.77	2.98-3.96
	Perimeter	16.36 ± 1.2	15.39 ± 0.79	15.59 ± 0.96	16.37 ± 1.1	16.88 ± 1.05	17.57 ± 1.21
		15.73-16.99	14.98-15.8	15.08-16.09	15.79-16.94	16.37-17.4	17-18.15
Left ear	Length 1	6.48 ± 0.51	6.08 ± 0.37	6.17 ± 0.41	6.44 ± 0.41	6.71 ± 0.49	7.04 ± 0.39
		6.07-6.88	5.75-6.4	5.85-6.5	6.11-6.76	6.34-7.07	6.74-7.33
	Length 2	2.71 ± 0.33	2.4 ± 0.23	2.55 ± 0.26	2.67 ± 0.29	2.85 ± 0.32	3.06 ± 0.27
		2.25-3.17	2.08-2.72	2.26-2.85	2.27-3.08	2.48-3.21	2.75-3.36
	Width 1	3.68 ± 0.31	3.55 ± 0.24	3.48 ± 0.26	3.7 ± 0.3	3.79 ± 0.29	3.91 ± 0.21
		3.33-4.03	3.28-3.83	3.19-3.77	3.28-4.11	3.46-4.11	3.71-4.11
	Width 2	3.26 ± 0.27	3.17 ± 0.23	3.12 ± 0.22	3.25 ± 0.24	3.34 ± 0.27	3.48 ± 0.26
		2.96-3.56	2.86-3.49	2.87-3.37	2.92-3.59	3.03-3.64	3.18-3.77
	Perimeter	16.46 ± 1.2	15.62 ± 0.92	15.66 ± 0.96	16.44 ± 1.01	16.98 ± 1.12	17.74 ± 0.92
		15.83-17.08	15.14-16.1	15.19-16.13	15.9-17	16.45-17.51	17.3-18.17

Table 4 Descriptive results for average sex-specific growth rates for both ears, (%/year)

	Sex	Length 1	Length 2	Width 1	Perimeter
Right ear	Male	0.14	0.25	0.13	0.14
	Female	0.19	0.27	0.16	0.19
Left ear	Male	0.14	0.25	0.20	0.15
	Female	0.19	0.29	0.14	0.17