I found an interesting blog that describes why we place our rings where we do. Most of it was in Chinese so I have posted a translated version.
Why wedding rings are put on our fourth finger(ring finger)(Please follow the steps below, God really made this a miracle)

1.Firstly, show your palm, bend your center finger and put them back to back (like above).
2.Secondly, the rest 4 fingers tips to tips.
3.Let the games begin, :) follow the below arrangement.
Oh, and here are the rules. Only 1 pair can split at a time.
4.Try to open your thumb. Your thumb represent your parents. Everyone must pass on to heaven, which is why our parents will leave one day.
5.Please close up your thumb, then open your second finger. This finger represents brothers and sisters. They have families to which they belong and they will leave as well.
6.Now close your second finger and open up your little finger, this represents your children. They too will leave for they have their own life to live.
7.Now close up your little finger and open your ring finger. You will be surprised to find that it cannot be opened at all. This represents husband and wife, and through life you will be joined together.
Love remains inseparable forever.
Credit:
Chinese version.Alabama, Bridal, Bride, Wedding, Wedding Rings, Weddings, LoveLabels: Alabama, Bridal, Bride, Wedding, Wedding Rings, Weddings