[The quadriga phenomenon of the extensor tendon system and the superficial transverse metacarpal ligament].

The aponeurosis of the common extensor tendons is connected by intertendinous connections proximal to the metacarpophalangeal joints. These fibers are responsible for tenodesis effects in case of maximal finger extension and flexion and by this means they diminish the function of the other metacarpophalangeal joints. This mechanism can be described as the Quadriga-Syndrome of the extensor apparatus. These connecting structures also help to stabilize the transverse metacarpophalangeal arch and the position of the extensor tendons over the metacarpal heads. Cadaver dissections as well as operative findings have shown that there exists a superficial transverse intermetacarpal ligament, which connects the metacarpal heads in the area of its neck.