Acromial shapes

1-The under surface of the acromion should be normally flat(type 1).

2-It could be taking one of the following shapes:

-Concave inferior surface---No effect on the supra spinatus muscle(type 2).

-Convex inferior surface(type 4).

-Inferior surface with hook or peak(type 3)---Which is the most dangerous type where it causes tearing of the supra spinatus muscle.

 

Impingement syndrome is a type of shoulder pain that results from inflammation in the subacromial area.  It can be simply from bursitis or synovitis, but most frequently is from bone spurs under the acromion or the acromioclavicular joint.  Some people are born with a predisposition for impingement syndrome due to an anatomically down-going acromion, termed a type 3 acromion.   Nonoperatively it is treated with anti-inflammatory medication or steroid injection.  Surgically it is treated with a subacromial decompression, literally shaving the spurs off.