Objective To observe the anatomy of the perforator flap of the posterolateral midforearm. Methods Lateral condyle of the humems wag taken as the observation mark on 30 specimens of adult upper limb perfused with red latex.The surgical magnifier Wag used to obse~e the origin,branches and distribution of the perforating branches of the posterolateral midforearm as well as alanagtomosis between perforating branches and peripheral vessels.Mimic operation WaS performed on the two sides of the fresh specimen.Results The perforating branches of the posterolateral midforearm originated from the radial musculoculancous branches of the posterior interosseous artery,the intermuscular branches of the radial artery and the direct periosteal branch of the radial artery had relatively stable location of piercing the deep fascia.Then,the perforating branches of the posterolateral midforearm pagsed through the deep fascia to the subcutaneous part among the spatium intermusculare of extensor digitorum and extensor carpi radialis brevis,supinator and abductor pollicis longus(within 12.5-15.8 cm below the lateral condyle of the humerus).Large number of small blood Vessels were also separated and closely aligned with the musculoculancous branches vascular,perineural and neural stem vascular chain of lateral branches of posterior antebrachial cutaneous nerve.Then,the vascular plexus was formed along the spatium intermusculare and lateral branches of posterior antebrachial cutaneous nerve longitudinal axis between extensor digitorum and extensor carpi radialis brevis. Conclusion The axial pattern flaps or cross-regional blood supply skin flap pedicled with the perforating branches of the posterolateral midforearm Can be formed to repair the soft tissue defect of tlle forearm and wrist.