Objective    To study the anastomotic types between the first metacarpal artery metacarpal neck ulnar perforator, the second dorsal metacarpal artery and the webbed artery, so as to provide anatomical basis for the safe design and incision of the second dorsal metacarpal artery flap.    Methods    A total of 39 fresh adult cadaveric hands were collected. All the arteries of those hands were perfused with red latex. Anatomical observation under the microscope was recorded not only the origin, course, and outer diameter of the first metacarpal artery metacarpal neck ulnar perforator, but also the anastomosis between the second dorsal metacarpal artery and the webbed artery.    Results    The first metacarpal artery metacarpal neck ulnar perforator branch started at the second metacarpal neck from the first metacarpal artery, with an initial diameter of (0.57±0.20) mm, and passed dorsally along the gap between the ulnar side of the second metacarpal artery and the interosseous muscles, forming anastomosis with the second dorsal metacarpal artery and the webbed artery. According to the anastomotic characteristics of the dorsal metacarpal artery and the webbed artery, it could be divided into 4 types: Ⅰ. Non-anastomosis type (accounting for 38.46%); Ⅱ. "T" type (accounting for 33.33%); Ⅲ. "Y" type (accounting for 25.64%); IV. "π" type (accounting for 2.56%). Conclusions   The anastomosis between 28.20% of the second dorsal metacarpal artery and the webbed artery are not direct, but indirectly anastomosed through the first metacarpal artery metacarpal neck ulnar perforator ("Y" type, "π" type anastomosis). In these two cases, it is easy to destroy the anastomotic continuity between the second dorsal metacarpal artery and the webbed artery during the operation, which may cause the difficulty or even failure of the second dorsal metacarpal artery flap operation.