<prompt> Swan-neck deformity is -Flexion of Metacarpophalangeal joint and extension at interphalangeal jointExtension at Proximal interphalangeal joint and flexion at Distal interphalangeal jointFlexion at proximal interphalangeal joint and extension at distal interphalangeal jointExtension at Metacarpophalangeal joint and flexion at interphalangeal joint  <response>: Important hand deformities of hand in RABoutonniere deformity: Flexion contracture of PIP joint and extension of the DIP joint.Swan neck deformity: Hyperextension of PIP joint and flexion at DIP joint.Z-deformity: Radial deviation of the wrist with ulnar deviation of fingers.Hyperextension of 1st interphalangeal joint and flexion of MP joint. 