The little finger and the mound just below it are ruled by Mercury.
Astrologically Mercury is the ruler of the zodiac signs of Gemini and Virgo and it is at home in the 3rd and 6th houses of the wheel. Mercury's element is Air. When associated with Virgo it is Earth.
Mythology
Mercury is the messenger God and is depicted as having winged sandals and carrying the cadeucus. He is the God of communication and mediation. He was also a divine manipulator. Mercury is considered the protector of thieves and businessmen. His Greek name is Hermes.
Hermes presided over magic, education and culture. He is said to have invented the alphabet.
Astrological Meaning
In the natal chart Mercury rules intellect, voice, communication, mediation, tactics, mental flexibility, judging, logic, resourcefulness and health. Archetypally, Mercury may be the messenger, the poet, the salesman, the critic, the teacher and the student both, the healer and the analyst.
On the negative side Mercury may often manifest as the Trickster, crafty, calculating and false. Negative Virgo manifests as the critic.
Mercury in your Hand
Such a small area of the hand reveals a lot about its owner. Keywords for Mercury are communications, ingenuity, negotiations, invention, intimacy, strategy, marketing, healer.
A long Mercury finger indicates that the subject is quick, sharp and clever though not necessarily a good communicator. A bent Mercury finger may imply issues regarding trust. A low set Mercury finger reveals fears about abandonment.