The ring finger refers to the fourth digit of each hand, located between the middle and pinky fingers.

The ringer finger is comprised of three phalanges, or bones, extending from the hand's fourth metacarpal bone. The proximal phalanx provides the base of the finger, which connects to the intermediate phalanx via the knuckle joint. At the end of the finger, the distal phalanx provides support to the sensitive pulp of the fingertip. The extensor digitorum muscle extends this finger, while the palmarand dorsal interossei flex the finger and move it toward and away from the middle finger. The radial and ulnar nerves supply these muscles.

Oxygenated blood arrives at the finger through the common palmar artery, which extends off of the palmar arch connecting the ulnar and radial arteries. The ulnar artery is the main supply of blood to the ring finger. The median, radial, and ulnar nerves provide sensory innervation to this finger.

In Western cultures, it is common for people to wear engagement and wedding rings on the fourth digit, often on the left hand.

The sports injury “jersey finger” is most common in the ring finger. This injury occurs when the tendon at the topmost joint of the finger is pulled off the bone. It is typically caused when someone pulls on another’s jersey and catches their finger. Surgical repair is often necessary to fix this injury.