Extensor expansion

The dorsal aponeurosis of the fingers is a fascia, which attaches to the back of the hand at the end link of the finger passes over the middle phalanx and at the level of the proximal phalanx volar side ( volar ) towards forming an approach to the interossei and lumbrical Musculi. As the origin of palm- side ( palmar) is the joint axis of the metacarpophalangeal joints, contraction of these muscles leads to diffraction in the metacarpophalangeal joint. Due to the further course towards the fingertip on the back of the finger occurs in the dorsal aponeurosis tension to an elongation of the middle and end joints of the fingers.

To allow extension in the metacarpophalangeal joint is the finger extensors ( extensor digitorum ), which comes from the forearm, back of hand side here of the joint axis.

A dorsal aponeurosis with basically the same design is also found on the dorsum of the foot.