Take the right hand as an example. When the palm of the right hand is upward, the first finger on the left is the little thumb, which is the smallest and weak finger among the five fingers. People regard the thumbs up as saying that others are weak and incompetent. It also has the meaning of ridicule and contempt.
In most cases, we have five fingers on one palm. They are named thumb, index finger, middle finger, ring finger and little thumb. Many people just know these five names, but they don't know which fingers they correspond to.
Take the right hand as an example. When we put the palm of our right hand upward, our five fingers are the little thumb, ring finger, middle finger, index finger and thumb from left to right. The little thumb is the smallest and weak of our five fingers, because it is rarely used.
Because the little thumb is small and weak, people also regard giving others a little thumb as saying that others are weak and incompetent. It also has the meaning of ridicule and contempt. In addition, wearing a ring on your little finger is also of special significance.