Signs and symptoms of a dislocated elbow include:

• Extreme pain
• Obvious distortion of the joint

Toddlers with nursemaid's elbow might experience pain only when the affected elbow is moved. A child often avoids using the arm and holds it slightly flexed next to the body.

Sometimes, the elbow is only partially dislocated. Partial dislocation can cause bruising and pain where the ligaments were stretched or torn.

In adults, the most common causes of a dislocated elbow include:

• Falls. Falling onto an outstretched hand can pop the upper arm bone out of alignment within the elbow joint.
• Motor vehicle accidents. The same type of impact can occur when passengers in motor vehicle accidents reach forward to brace themselves before a collision.

In children or teenagers, falling onto an outstretched hand is also a common cause of a dislocated elbow.

In toddlers, the injury often occurs when an extra pulling motion is applied to an outstretched arm. The causes of such injuries include:

• Improper lifting. Trying to lift or swing a young child by the arms can cause the elbow to dislocate.
• Sudden pulling. Having the child suddenly step off a curb or stairstep as you're holding his or her hand can pull the elbow out of alignment.

• Age. Young children's elbows are much more flexible than those of adults. So it's easier for younger elbows to become dislocated.
• Heredity. Some people are born with elbow ligaments that are looser than those of most people.
• Sports participation. Many elbow dislocations are sports-related. Sports that require weight bearing with the arms, such as gymnastics floor exercise, are especially risky for elbow dislocations.

Complications of a dislocated elbow can include:

• Fracture. The force that dislocates the elbow might also cause a fracture in one of the elbow bones.
• Pinched nerves. Rarely, nerves that travel across the elbow can become pinched or trapped between the dislocated bones or within the joint when the bones are realigned. Pinched nerves can cause numbness in the arm and hand.
• Trapped arteries. Rarely, blood vessels that supply the arm and hand can become pinched or trapped between the dislocated bones or within the realigned joint. Lack of blood supply can cause severe pain and permanent tissue damage in the arm and hand.
• Avulsion fractures. In some elbow dislocations, a stretched ligament will pull off a tiny bit of bone from its attachment point. This type of damage is more common in children.
• Osteoarthritis. The dislocated joint may be at higher risk of developing osteoarthritis in the future.