Index finger

The index finger is the finger of the hand adjacent to the thumb, and is the second finger when counting from the thumb side. It is also called the pointing finger or forefinger in some regions. The English term 'index finger' derives from its use in pointing or indicating (index = to indicate).

The index finger, like the other non-thumb fingers, consists of three bones called phalanges (finger bones), connected by joints. It is attached to one of the metacarpal bones (palm bones) of the hand. Some of the muscles that move it are located inside the hand, others in the forearm, connected to the finger by tendons.

Structure

The three bones are distinguished as the one at the base of the hand, the middle one, and the one at the tip. The tip end has a fingernail. On the palm side of the finger lies a ridge bearing a fingerprint (sawir-far) unique to each person, making it useful for human identification.

Function

The index finger plays a major role in grasping small objects, working in coordination with the thumb. Coordination between thumb and index finger is used to grip writing implements such as pens, and tasks requiring fine motor control. It is also the finger most frequently used to touch screens and buttons.

Social and religious use

The index finger is used to point and indicate things. In many cultures, pointing with this finger is considered impolite. In Islam, the index finger is raised when reciting the shahada (declaration of faith) in the tashahhud during prayer. In many countries it is also used to mark ballots with ink that is difficult to wash off.