Metakarpalknogle

Metakarpalknogle is the term used in several Scandinavian languages to refer to the metacarpal bones of the hand. These are the five long bones that lie between the carpal bones of the wrist and the phalanges of the fingers. Each metakarpalknogle has a base that articulates proximally with the distal carpal row, a shaft, and a distal head that forms the metacarpophalangeal joint with the proximal phalanx of the corresponding finger.

The five metakarpalknogle are numbered I to V from the thumb toward the little finger. The first metakarpalknogle (associated with the thumb) is comparatively short and robust and participates in a specialized carpometacarpal joint that allows thumb opposition. The second through fifth metakarpalknogle are generally longer and more slender, contributing to the curved shape of the palm and to grip mechanics.

Joints between the metakarpalknogle and adjacent bones include the carpometacarpal joints at the base and the metacarpophalangeal joints at the heads. The former connect the metacarpals to the distal carpal row and, for the thumb, enable a wide range of thumb movement; the latter form the knuckles, allowing finger flexion, extension, and, in the later joints, some abduction and adduction.

Functionally, the metakarpalknogle provide structural support for the palm, contribute to the arch of the hand, and enable gripping, pinching, and fine motor actions. Anatomical variation exists in length, alignment, and curvature among individuals. Clinically, metakarpal fractures are common injuries, with the fifth metakarpal neck fracture (boxer's fracture) being a well-known example requiring medical assessment and management.