Acromion and Rotator Cuff in my shoulder MRI results

Dear Ask The Doctor: I was told i have Lateral downsloping of my acromion which is resulting in lateral arch narrowing, what does this mean, and how was it caused? I also have no tear, fracture, or dislocation of my rotator cuff, yet there is tendinosis and peritendinitis of my supraspinatus tendon, How is that caused/treated?

Dear Joseph:

There is a part of the rotator cuff tendon that passes under the acromion in a sort of channel between the articular capsule and the subacromial-subdeltoid bursa , and if the acromion is “downsloping” the resulting narrowing in this space will involve the Rotator Cuff tendon causing its inflammation (tendinitis or tendinosis). The lesion, then,  results mainly from repeated impingement of the rotator cuff tendon against different structures of the glenohumeral (shoulder) joint.

The conservative treatment of the degenerative rotator cuff involves: avoidance of painful motions and activities, anti inflammatory medications, manual physical therapy, stretching of the glenohumeral capsule and muscles, subacromial corticosteroid injection, and a new promising procedure called the bupivacaine suprascapular nerve block.