(A) Pathogenesis In addition to gun and bullet injuries, local fracture and stab wounds are also common. (II) Pathogenesis The brachial artery is connected to the axillary artery (the lower edge of the great circular muscle) and ends 2.5 cm below the elbow fossa; then it is divided into two branches: the ulnar artery and the radial artery. In addition to gunshot and shrapnel wounds, fractures of the humeral stem and supracondylar humerus are the usual causes of damage. In the middle part of the humerus, the radial nerve and median nerve are easy to be injured, and in the upper part of the condyle, the median nerve is mainly involved, and the total incidence can be 60% to 70%.