Dermatoglyphics

Dermatoglyphic is is the study of the skin ridges in our hands, especially the fingerprints, though on some hands there are glyphs to be found on the palm itself. Fingerprints are fully formed 16 weeks after conception, a full 5 months before you enter the world, and they will never change.

Each fingerprint is composed of between 50 and 100 lines. Though no two fingerprints are exactly alike, prints can be classified into one of four major types: the whorl, the loop, the arch and the tented arch. There are also two subtypes of the whorl. The peacock looks exactly as the name suggests, like the eye on a peacock tail feather. The composite resembles a yin/yang symbol, two loops swirling around each other.
In general, a preponderance of a particular type of fingerprint can tell you about the basic temperament of the subject.

Whorl
People with many whorls on their hands like to be in charge. They are often deep thinkers and may be dogmatic in their viewpoints. The whorl can be associated with the element of Fire.

Loop
This is the most common fingerprint. It denotes flexibility and a dislike for routine. Subjects with many loops may display an emotional nature. The loop can be associated with the element of Water.=

Arch
Arches on the fingertips can indicate someone who has trouble expressing their emotions. The owner of these fingerprints can be practical in nature and may find change to be unwelcome. The arch can be associated with the element of Earth.

Tented Arch
This print is usually found only on the index finger, though I have seen hands where they appeared on the middle and ring fingers as well. This mark is a sign of a sensitive, impulsive nature. People with tented arches may be seekers of the truth and may tend toward perfectionism. The tented arch can be associated with the element of Air.

Other Glyphs on the Hand
A common occurrence of a glyph on the palm may be found between the fingers. A loop between the Mercury and Apollo fingers is called the Loop of Humor. Having this loop indicates a subject with an optimistic outlook and a good sense of humor. A loop between Apollo and Saturn is called the Loop of Seriousness. People with this loop exhibit common sense and may feel a great sense of responsibility in their lives.
Less common is a loop between Saturn and Jupiter. Called the Rajah Loop, it was once thought that this marking indicated descent from royal lineage. One author has renamed this mark the Loop of Charisma. It can be viewed as a mark of executive ability.