Why is the fourth finger the ring finger?

I saw this and thought it was neat:

Why should the wedding ring be worn on the fourth finger? This is a beautiful and convincing explanation given by the Chinese .... Thumb represents your Parents Second (Index) finger represents your Siblings Middle finger represents your own Self Fourth (Ring) finger represents your Life Partner and the Last (Little) finger represents your children Firstly, open your palms (face to face), bend the middle fingers inward and hold them together - knuckle to knuckle Secondly, open and hold the remaining three fingers and the thumb - tip to tip Now, try to separate your thumbs (representing the parents) They will open, because your parents are not destined to live with you lifelong, and have to leave you sooner or later. Now join your thumbs as before and separate your Index fingers (representing siblings) They will also open, because your brothers and sisters will have their own families and will have to lead their own separate lives. Now rejoin the Index fingers and separate your Little fingers (representing your children) They will open too, because the children also will get married and settle down on their own some day. Finally, join your Little fingers, and try to separate your Ring fingers (representing your spouse). You will be surprised to see that you just CANNOT --- because Husband & Wife have to remain together all their lives - through thick and thin!! Neat, huh?