The elbow is the hinge joint of the arm. When the joint surfaces of the elbow are separated, the elbow is dislocated. Elbow dislocations can be complete or partial, and usually occur after a trauma, such as a fall or accident. In a complete dislocation, the joint surfaces are completely separated. In a partial dislocation, the joint surfaces are only partly separated. This is called a subluxation. Symptoms include extreme pain, obvious deformity, odd twist at the elbow, and bruising.