A 68-year-old woman from Delhi falls on her outstretched hand while climbing stairs. She presents to the emergency department with severe pain and swelling over the dorsal aspect of the wrist. On examination, the wrist shows a characteristic 'dinner fork' deformity. X-ray confirms a fracture of the distal radius with dorsal angulation and dorsal displacement of the distal fragment. Which of the following best describes the mechanism of injury in this fracture?