Shoulder instability (dislocated shoulder) Symptoms & Causes

About the shoulder joint

The shoulder (glenohumeral) joint is remarkable for its wide range of motion in just about any direction. But the downside of being able to move in so many directions is that it is relatively easy to dislocate. In fact, shoulder dislocations account for up to half of major joint dislocations. 

Will my child be OK?

After a shoulder dislocation and reduction, recurrent instability can occur, , especially in adolescent athletes who play contact sports. Some children and adults with looseness (laxity) are more likely to have repeat dislocations. Young, active patients do run up to a 80 percent risk of recurrent instability.

Shoulder dislocations anterior and posteriorCauses of shoulder instability

Three main ligaments attach the end of the upper arm’s long bone (called the humeral head) to the “socket" part of the shoulder (called the glenoid), and each ligament tightens at different arm positions to hold the shoulder together. A dislocation can occur when the ligaments are torn or stretched. 

A dislocation can also occur when there is a problem with muscles and tendons that wrap around the shoulder and hold the bones in place (called the rotator cuff). Problems with the bones of the shoulder can also lead to dislocations. 

The shoulder can dislocate forward if your child's arm is struck when his shoulder is abducted and externally rotated—as in the blocking position of a football linebacker. It can dislocate backward due to a fall onto an outstretched hand or from a direct blow to the front of the shoulder.

Signs and symptoms of a dislocated shoulder

•   Pain in the shoulder and upper arm pain, especially with movement
•   Difficulty moving the upper arm
•   Deformity, like a bump, in the front or back of the shoulder