Fig. 5
The subacromial height (red dotted lines) must be maintained when the arm is alongside the body. However, when the arm is raised, the greater tuberosity abuts the lower edge of the acromion and the subacromial height becomes almost zero. a When the arm is in neutral position next to the body, the supraspinatus tendon helps to maintain the subacromial height. When the arm is raised, the tendon escapes towards the supraspinatus fossa, leaving the place for the greater tuberosity. b Example of the subacromial spacers that maintain subacromial height when the arm is alongside the body. They may interfere with the course of the greater tuberosity when the arm is elevated because they remain in the subacromial space. c the GRAST graft has a mechanical action similar to that of the supraspinatus tendon. (images belong to the author Marc Soubeyrand)