Head and neck reconstruction using ulnar forearm flaps has several advantages; however, it is still considered challenging because of the small venous diameter. Between January 2020 and September 2022, 24 patients underwent head and neck reconstruction using ulnar forearm flaps in Shimane University Hospital. The patients were 27-79 years old, and the postoperative follow-up period was 143-1126 days. The average diameter of the ulnar artery was 2.0 mm. Of the two accompanying veins, the larger vein had an average diameter of 1.2 mm, and the smaller vein had an average diameter of 1.0 mm. The cutaneous veins of the flap had an average diameter of 1.6 mm, consisting of 14 median antebrachial veins and five basilic veins, but they were absent in five cases. The ulnar vein was frequently anastomosed to the internal jugular vein in an end-to-side fashion. Overall, 18 out of 24 patients（75%）had two ulnar veins anastomosed to the internal jugular vein. Postoperatively, the flap survived completely in 23 cases, excluding one case where partial necrosis occurred. Anastomosing two ulnar veins to the internal jugular vein in an end-to-side fashion may be effective, and all possible venous anastomoses may be recommended to avoid flap compromise.
