Shoulder dislocation and shoulder separation are commonly confused. Though they are both very serious injuries, they are completely different.
Bones of the shoulder joint
There are three bones that make up the shoulder joint:
the humerus (upper arm bone)
the scapula (shoulder blade)
the clavicle (collar bone)
We often think of the shoulder as a singular joint. In fact, there are two joints within the shoulder complex:
Glenohumeral Joint � the ball of the humeral head (this is the ball on the end of the upper arm bone) which fits into the glenoid or socket of the scapula.
Acromioclavicular Joint � this is where the end of the collar bone meets the acromion (the end of the scapula), this is also known as the A-C joint.
A dislocation occurs when the glenohumeral joint is disrupted and the humerus (ball) and the scapula (socket) are no longer in contact. In fact, they are dislocated from one another
A separation occurs when the acromioclavicular joint is injured. There are six types, grades or levels of separation, with each being defined by the severity of the injury sustained. This is also commonly known as an A-C separation.
Often you will hear someone say that they have a partial shoulder separation. In all likelihood. they have been diagnosed with a type I or a type II A-C separation.
Similar but not the same
Shoulder dislocation and shoulder separation are often confused with each other, but they are different, requiring different treatments and could possibly lead to different future complications. Make sure that your doctor explains your exact injury to you in as much detail as you need, so that you understand your situation.