A variety of fractures and fracture-dislocations occur about the base of the thumb. With the exception of the extra-articular fracture of the metacarpal base, most of these injuries are best treated surgically. Closed reduction with percutaneous fixation should generally be attempted, with open reduction being reserved for cases in which residual joint incongruity persists following attempts at closed reduction. Pronation of the distal fragment is important for reduction of Bennett's fracture, as well as for apposition of the volar oblique ligament in trapezial fractures and trapeziometacarpal dislocations. The optimal treatment method for Rolando's fracture has not been established, although external fixation with limited internal fixation of the metacarpal base appears promising. Knowledge of the anatomy and deforming forces in these injuries will allow appropriate treatment and restoration of function in the important trapeziometacarpal articulation.