Anatomy and functional significance of the long extensors to the fingers and thumb

Intrinsic and extrinsic hand muscles power finger extension. These two musc le groups have different anatomy that allows complimentary function at the interphalangeal joints and opposing function at the metacarpophalangeal joi nts. Independent extension of each finger is not possible because of anatom ic constraints including the juncturae tendinum and intertendinous fascia b etween the extrinsic extensor tendons on the dorsum of the hand. Anatomic v ariations of the extrinsic extensor tendons are frequent and knowledge is i mportant when assessing the traumatized or diseased hand.