The detachment of the superior labrum from anterior to posterior has previously been reported. This lesion has been classified into four types. It was our impression that not all superior labrum abnormalities fit into such a classification system and that the mechanism of injury was distinctly different. During a 5-year period, 84 of 712 (11.8%) patients had significant labral abnormalities; 52 of 84 patients (6.2%) had lesions that fit within the classification system (Type II, 55%; III 4%; IV, 4%), but 32 of 84 patients (38%) had significant findings that could not be classified. These unclassifiable lesions fit into three distinct categories. Two of three patients described a traction injury to the shoulder. Only 8% sustained a fall on an outstretched arm; 75% had a preoperative diagnosis of impingement based on consistent history and provocative testing; however, when examined under anesthesia, 43% of the shoulders were considered to have increased humeral head translation when compared with the other shoulder. Recognition of superior labrum-biceps tendon detachment should prompt the surgeon to investigate glenohumeral instability as the source of a patient's complaints.