Elbow hyperextension occurs when the structures that connect these bones are pushed beyond their natural range of motion. Basically, your elbow gets bent too far in the wrong direction from a straightened position. A hyperextended elbow may cause ligament or tissue damage and may even temporarily inhibit full movement of the elbow.
During injury, the patient may hear a "popping" sound. One of the symptoms of elbow hyperextension is pain when the arm is in a straightened position. Some patients also have persistent pain at the front of the elbow (the side that creases when the elbow is bent). In some cases, swelling may be present and the patient may also experience muscle spasms in the bicep when attempting to straighten the arm.