The shoulder can be a ball-and-socket joint that is definitely built up of 3 bones: the higher arm bone, shoulder blade and collarbone. Causes of Shoulder Instability / Dislocation Shoulder instability and dislocation can happen due to various causes, such as: Trauma: A unexpected and forceful influence or injury into https://www.theorthopaedicandpainpractice.com/what-are-shoulder-joint-dislocations/?_gl=1*164kc8h*_up*MQ..&gclid=Cj0KCQjwkt6aBhDKARIsAAyeLJ2krYJSOuy5mZksrNqH-VDjQwW1ScD49yD8BUWysDG6u6bJPCSbXVUaAuCPEALw_wcB