A shoulder hyperextension is also known as a shoulder dislocation. When you hyperextend your shoulder, the upper arm bone -- or humerus -- has become dislocated from the ball-and-socket joint of the shoulder known as the glenoid. A fall onto an extended arm, trauma such as an auto accident or a direct collision in sports can lead to shoulder hyperextension. This condition is painful and requires immediate medical attention.
Check for symptoms. You are likely to experience pain, swelling, bruising and numbness if you have dislocated your shoulder. You may also experience muscle spasms.
Look in the mirror. Examine your shoulder for signs of a visual deformity. Your affected arm may appear to be longer than the other arm, or your shoulder joint may appear to be loose.
Visit a doctor or emergency room as soon as possible. A doctor will take a medical history, inquire about how you injured yourself and examine you. A physical examination along with X-rays will likely occur. At this point, your doctor will determine the appropriate treatment plan for you. A doctor will normally reduce -- or put back into place -- your shoulder joint. Severe pain will decrease shortly thereafter.
Left untreated, shoulder hyperextension can cause permanent damage to the tendons and nerves of your shoulder and upper arm.