why the wedding ring is on the fourth finger

In Western cultures a wedding ring is traditionally worn on the ring finger. According to tradition in some countries, the wedding ring is worn on the left ring finger because the vein in the left ring finger, referred to as the vena amoris was believed to be directly connected to the heart, a symbol of love.

In medieval Europe, the Christian wedding ceremony placed the ring in sequence on the index, middle, and ring fingers of the left hand, representing the trinity — God the Father, God the Son, and God the Holy Spirit. The ring was then left on the ring finger. In a few European countries, the ring is worn on the left hand prior to marriage, then transferred to the right during the ceremony. For example, a Greek Orthodox bride wears the ring on the left hand prior to the ceremony, then moves it to the right hand after the wedding.

In Norway, Russia, Bulgaria, Poland, Germany, Austria, Denmark, Latvia, some countries of former Yugoslavia and in Spain (except in Catalonia) the wedding ring is worn on the ring finger on the right hand.

In the Jewish wedding ceremony, the groom places the ring on the bride's index finger, and not ring finger; the ring is usually moved to the ring finger after the ceremony.

In the Indian tradition, the left hand is considered suspicious. Hence the wedding ring is worn on the right hand. However, despite tradition, some wear the ring on the left hand, matching cultural practice in some western countries.