Bennet fracture dislocation involves base of -

Ans. is 'a' i.e., 1st metacarpal * Benett's fracture is an intra-articular fracture dislocation of the palmar base of first metacarpal bone of the thumb with either subluxation or dislocation of first carpometacarpal joint, i.e. trapezometacarpal joint. The common mechanism of injury is an axial blow directed against the partially flexed metacarpal, in most cases during "Fist fights". Patient complains of pain, swelling and tenderness over the base of the thumb. Movements of thumb are restricted.