OBJECTIVE: To investigate the anatomic basis for transposition of the distal dorsal ulna bone flap pedicled with dorsal metacarpal artery to repair the defect of the 3rd or 4th and 5th metacarpal bone head. METHODS: In 30 adult cadaveric upper limbs, the branches and constitutions of the dorsal carpal arterial networks were observed. RESULTS: The dorsal carpal arterial networks were consisted of the dorsal carpal branches of ulnar and radial arteries, the terminal branches of posterior interosseous artery and the dorsal carpal branch of anterior interosseous artery, and then the 2nd, 3rd, 4th dorsal metacarpal branches were originated from the networks. The dorsal metacarpal branches were anastomosed with the deep branches of deep palmar arch to constitute the dorsal metacarpal artery. CONCLUSION: Transposition of the distal dorsal ulna bone flap pedicled with the 3rd, 4th dorsal metacarpal arteries can be used in repairing the defect of 3rd, 4th and 5th metacarpal bone head.