Treatment of pseudoarthroses of the scaphoid bone remains a difficult surgical problem. In many cases, it is not enough simply to stabilize the bone with a free bone graft. A pronator quadratus osteomuscular transposition flap has been used since 1983 to revascularize and stabilize the traumatized scaphoid hone. The precise vascular supply of the pronator quadratus muscle has been determined by a study of 5 injected cadaver anatomic preparations, 26 clinical cases are reported using this transposition flap.