falangene

Falangen (the falanges) are the small bones that form the digits of the hands and feet in humans and many other vertebrates. They are arranged in three groups from the base toward the tip: proximal, middle, and distal phalanges. In humans, the hand contains 14 phalanges: the thumb (pollex) has two (proximal and distal), while each of the other four fingers has three (proximal, middle, distal). The foot has the same arrangement, so each foot contains 14 phalanges. Across both hands and both feet, an adult human typically has 56 phalanges.

Each phalanx is a long bone with a shaft and expanded ends that form joints. The proximal phalanx of each finger articulates with a metacarpal bone at the metacarpophalangeal joint; the distal phalanx articulates with the middle phalanx at the distal interphalangeal joint, or with its partner at the interphalangeal joint in the thumb. In the toes, the analogous joints occur between phalanges and metatarsals (metatarsophalangeal joints) and between adjacent phalanges (interphalangeal joints).

Phalanges provide the form and length of the digits, enable flexion and extension for grasping and manipulating objects, and, in the feet, bear weight and aid balance during locomotion. They ossify from primary and secondary centers during fetal development, and counts are relatively consistent in humans though variation exists across species. Fractures and dislocations of the phalanges are among the most common skeletal injuries and are typically treated with immobilization or realignment.

Etymology: The term derives from the Greek phalanx, via Latin, reflecting the linear arrangement of bone segments in the digits.