FIGURE 109.9 This lateral radiograph demonstrates a small volar avulsion fracture of the proximal middle phalanx (A ), then a larger pilon fracture of the proximal middle phalanx (B ) (Courtesy of Children’s Orthopaedic Surgery Foundation.) Proximal phalanx injuries to the thumb are unique In adolescents and adults, a skier’s or gamekeeper’s thumb occurs with rupture of the ulnar collateral ligament (UCL) during an abduction stress of the thumb In children, a fracture of the base of the proximal phalanx is more likely than a UCL injury, with Salter– Harris I and II fractures predominating in younger children and Salter–Harris III fractures in older children Thumb spica splinting is appropriate for this constellation of injuries in the emergency department Extra-articular injuries may