Table 1.

Common bile duct diameters in each age group

Group number	Age (yr)	Patient number	Common bile duct diameter Mean ± SD (mm)
I	≤ 20	42	3.23 ± 0.77
II	21-30	123	3.45 ± 0.67
III	31-40	137	3.80 ± 0.97
IV	41-50	234	4.01 ± 0.89
V	51-60	155	4.50 ± 1.11
VI	61-70	113	4.83 ± 1.18
VII	> 70	58	5.12 ± 1.10