The patient was a 19-year-old male with skin necrosis, tendon deficiency, and open joint capsule following a thermal compression injury. A left transverse wrist flap was designed, and in this case the flap had only one ulnar branch, which was well developed. There was no penetrating branch on the radial side. Anatomical basis: There are two to three radially directed radial arteries in the lower radial artery (within 50 mm of the tip of the radial styloid process) and zero to two ulnarly directed dermatologic arteries. These dermal arteries have extensive traffic and anastomosis with the dermal branches of the arterial network of the wrist and are very constant. Flap design concept: Any branch can be free for grafting as long as it forms a balanced system of arteriovenous return. Design path: The line from the radial tuberosity to the navicular tuberosity is the axis of the flap, and the extent of excision does not easily exceed the lateral midline of the forearm, with the upper border to the distal 1/3 of the forearm and the lower border to the transverse wrist. Although there is a little tension blister after the operation, the flap survival is not in danger.