The extensor plus finger is a rare condition, in which there is such tension of the extensor hood mechanism that simultaneous, complete flexion of the metacarpophalangeal joint and the interphalngeal joint is impossible. Full flexion of the metacarpophalngeal joint compels the interphalngeal joints to extend and vise versa. This condition is a severe handicap to grasp. The extensor plus state is produced by any condition which shortens the excursion of the extensor hood mechanism over the metacarpophalngeal joint and proximal phalanx. When the extensor hood (central extrinsic extensor and sagittal band) is the villain of the extenaor plus state, stretching out the hood by tenotomies of the central extrinsic extensor restored normsl function immediately. We experienced four cases of the extensor plus finger of a patient with severe crushing open forearm bone fracture, and treated the cases by staggered tenotomies or complete tenotomies of the central extrinsic extensor and division of the sagittal band, and obtained a satisfactory result.