The true shoulder joint is where the head of the upper arm bone (humerus) inserts into a shallow cup in the shoulder blade. The cup is called the glenoid cavity. It’s a ball and socket joint.
ust above the true shoulder joint is a bony projection coming around from the back of the shoulder blade. This piece of bone is called the acromion. The end of the acromion meets the collarbone to form a shelf over the shoulder.
Pain from any of the structures around or above the shoulder joint can cause pain that seems like it’s coming from the joint. A careful exam by your doctor can pinpoint the exact cause. This is helpful information so the right problem is treated.