Juncturae tendinum

The juncturae tendinum are short fibrous bands that interconnect the extensor digitorum communis tendons proximal to the metacarpophalangeal joints. They permit coordinated finger extension and partially distribute extensor force between adjacent tendons. Their clinical significance is two-fold: they can mask a proximal tendon laceration on examination — the affected finger may still extend to some degree via neighbouring intact tendons — and they form the biomechanical substrate of relative-motion orthosis rehabilitation, in which the splint position transfers extensor force from a repaired tendon to its uninjured neighbours.