<prompt> Mallet finger is a flexion deformity of the distal phalanx, which occurs due toAvulsion fracture of middle phalanxRupture of collateral slips of extensor expansionRupture of central slip of extensor expansionDislocation of distal interphalangeal joint  <response>: Mallet finger is a flexion deformity of the distal phalanx due to injury to the extensor digitorum at its inseion to the base of the distal phalanx the collateral slips. 