Signs specific to joint dislocation include the following: first, loss of normal contour and bony relationship, such as square shoulder deformity in anterior shoulder dislocation, and loss of large nodes. In elbow dislocation, the posterior elbow is hollow and the depression can be felt, and the three-point posterior elbow relationship is completely destroyed and the normal relationship is lost; second, joint dislocation is often manifested by elastic fixation of the joint; third, posture, in hip dislocation is often manifested by limb flexion, inversion, internal rotation or abduction, lower limb external rotation and obvious shortening; fourth, combined neurovascular injury, the incidence of nerve injury in dislocation is higher than that of fracture. For example, sciatic nerve injury can easily occur in posterior hip dislocation, interosseous nerve injury can be combined with radial head dislocation, and popliteal artery injury can be combined with posterior knee dislocation, which can easily lead to local thrombosis; fifthly, loss of joint activities, in most joint dislocations, both active and passive activities are obviously limited or completely lost.