Classified based on the supraspinatus outlet view Originally described by Bigliani Acromial morphology has a noted assoicated with RTC tears (Pearsall AW, JSES 2003;12:122). Type 1 Flat acromial undersurface. Type II Downward curved acromial undersurface. Most common Type III Hooked acromial undersurface. Associated with increased incidence of Rotator Cuff Tear.