That’s a lot of info! You’re looking at the front of a right shoulder. But don’t worry you only need to pay attention to a few things.
The acromion (that flat bone on the top of your shoulder)
The subacromial space (space between the acromion and humerus)
The Supraspinatus (part of the rotator cuff)
Normally, when the arm lifts the subacromial space stays consistent and the humerus (upper arm bone) glides without issue throughout the entire range of motion. IF, when lifting the arm the humerus moves incorrectly it will trap the supraspinatus tendon in between the acromion and BAM! Impingement!
Now that we understand WHAT it is. Why does it happen? The answer is, just like most things in lift, not black and white.
Some of the most common causes are:
1. Repetitive overhead movements
2. Weakness of rotator cuff or scapular muscles
3. Poor Posture
4. Increased time sitting or driving
5. Genetics! (Sorry guys)
These are just a few of the most common reasons but as I mentioned before, the actual cause is usually a lot more gray! Actual diagnosis can be difficult due to the shoulder complex nature.
If you think you may be experiencing symptoms of impingement syndrome the best course of action is to reach out to your friendly neighborhood physical therapist for a proper evaluation and diagnosis!