Dislocation - complete displacement of the articular surfaces of bones forming the joint, which lost contact of the articular surfaces of joints. Usually accompanied by sprains breaks the joint capsule and ligaments. Incomplete separation of the articular surfaces is called subluxation.
The mechanism of traumatic injury resulting in dislocation occurred more often indirect. This decline in the straightened leg, sudden sharp contraction of the muscles, such as in sports. Dislocations may be closed and open, if the joint cavity through the wound surface is connected to the environment.
Complicated sprains occur when intra-articular or periarticular is broken. Such states are called perelomovyvihami. The frequency of dislocation of up to 3% of all traumatic injuries. Most sprains occur frequently in the joints of the upper extremities. Fresh dislocation is considered, if the date of injury was no more than 2 weeks. The term chronic dislocation is now rarely used.
Dislocation may become habitual, if the same joint after the primary dislocation and reduction, sprains recur. If the dislocation has no right soon after the injury, is developing very fast muscle contraction, which has the strong fixation of bone sprained her in the wrong position but in the vacant glenoid cavity develop inflammation, depression is filled with connective scar tissue and a conservative reduction of dislocation becomes impossible.