The elbow, being a true hinge joint, is one of the most stable joints in the body. It is formed by the articulation of the humerus, radius, and ulna. Dislocations of the elbow are rare, however, there seems to have been a few more elbow dislocations lately. It takes a very large force to dislocate the elbow, and most dislocations occur in the posterior (backwards) direction. If you do not like to look at pictures of injuries, I would advise you not to scroll down any further. But, if you do and would like to learn, take a look at the pictures and video.
This injury occurred this summer during the NBA playoffs. Rando, the injured player, got tangled up with Wade. As he landed, he put his arm out to brace his fall, and the force from the ground caused the resulting elbow dislocation. 
This injury occurred during the 2008 Bejing Olympics. The weightlifter was attempting to lift a very large amount of weight, and the force from the barbell caused the forearm to be forced posteriorly (backwards) in relation to the upper arm.This injury occurred last week during the Oregon-California game, and was very similar to the basketball injury. The running back was being tackled and when he attempted to brace his fall, he dislocated his elbow. Once a physician reduces the dislocation, it is possible to make a fairly quick return to play (except for the weight lifter) while wearing an elbow brace to stabilize the joint. This must be treated as a serious injury, because there are many nerves and blood vessels that run behind the elbow that could be damaged by the dislocation.
