Applied Anatomy Of First Dorsal Metacarpal Artery Reversed Island Skin Flap

Objective:To provide the anatomical basis of the application of the first metacarpal arteryretrograde island flap. Methods:The origin, diameter, length,anastomoses with the distal artery,the amount and the diameter of accompanyingvein of the first metacarpal artery were explored andobserved in58sides of adult cadaveric hand specimens with10%formaldehyde fixed. The originand distribution of the first metacarpal island flap sensory nerve were observed. Arteriography wasused in one side of an unfixed adult cadaveric to observe the first metacarpal artery. Results: Thefirst metacarpal artery were originated from radial artery snuffbox section, the diameter and thelength of first metacarpal artery was（0.77±0.19）mm and (5.21±0.47)cm separately. The firstmetacarpal artery can be divided into three types: The regular type35sides(60%), this type canalso be divided into tree types as follows outermuscular type28sides, Intramuscular type6sidesand mixed type1side according to different position of the first metacarpal artery. This type waslocated in the radial side of the second metacarpal anastomosed with the radial proper digital arteryof index finger at second metacarpal cervix or radial side of the proximal phalanx of the indexfinger.The variation type17sides(29.2%),were divided into the multiple-branch type7sides(12%)and the principal artery of thumb type10sides(17.2%),reticular anastomoses can be observed atthe second metacarpophalangeal joint, the principal artery of thumb type anastomosed with thesuperficial palmar arch at the middle point of the thumb web periphery. The absence type6sides(10.3%).The first metacarpal artery accompanied two veins with mean diameter(0.4±0.15)mm，11sides(39%) accompanied one vein with mean diameter(0.5±0.1)mm，30sidesaccompanyingvein were not be seen. The sensory nerves of the first metacarpal artery island flapwere originated from superficial radial nerve.Conclusions: The regular type as the flap axes arterycan be designed to rapair soft tissue defect in proximal thumb and index finger or dorsalmetacarpophalangeal joint. The variation type should be cautiously use and The absence typeshould not be use to design retrograde island flap.