Posteroanterior (PA) (Fig. 64A) and lateral (Fig. 64B) radiographs of the left thumb reveal an oblique intra-articular fracture at the volar medial aspect of the metacarpal base. PA (Fig. 64C) and oblique (Fig. 64D) views of the left hand coned on the thumb in another patient demonstrate an impacted comminuted intra-articular fracture of the thumb metacarpal base; the pattern of comminution can be described as either “T-shaped” or “Y-shaped.”