Mallet finger is due to -

Ans. is 'a' i.e., Avulsion of extensor tendon from base of distal phalynx Mallet finger (Base ball finger)* Sudden passive flexion of the distal interphalangeal joint (as by a ball striking the tip of the finger) may rupture the extensor tendon at the point of its insertion into the base of distal phalanx.* Sometimes, a fragment of bone is avulsed from the phalanx.* Clinically, distal phalanx is in slight flexion and patient is unable to extend DIP joint fully.* Treatment is by immobilizing the DIP joint in hyperextension with the help of an aluminium splint (finger extension splint) or plaster cast.