There are various descriptions of labral injuries which are identified in glenohumeral arthrography.  A SLAP tear involves the origin of the long head of the biceps and its attachment on the superior labrum, and differentiating with a sublabral sulcus is one aspect in interpreting shoulder MRIs.  A Perthes lesion will have an intact periosteum.

Clock face terminology is used in the descriptions of labral injuries, but one should bare in mind 3 o'clock can mean both anterior and posterior positions at the equator. Therefore if clock face descriptions are used, the 3 o'clock position should be referenced in the report.