The life line runs from the area between the thumb and forefinger and continues downward toward the bottom of the wrist. It is different for different people. Most of the people may think the line is used to see the duration of one's life. It's a partial understanding. In fact, it mainly reflects a person's physical vitality and life energy.
The head line (also wisdom line or intelligent line), one of the main lines in palm reading, is primarily related to the mental state of a person. It starts from the palm edge between the thumb and forefinger, and runs horizontally across the middle of palm with the life line below and the heart line above.