Fig 1.

Endoscopic classification of neurovascular bundle (NVB) patterns was evaluated intraoperatively based on alignment of the nerve, artery, and vein, following 3 types: parallel type, in which the artery and nerve travel parallel (A and D), oblique type, in which the nerves are partially behind the artery (B and E), and vertical type, in which the nerves are totally behind the middle scalene muscle or abnormal band (C and F). Abbreviations: A, artery; ASM, anterior scalene muscle; MSM, middle scalene muscle; N, nerve; V, vein.