SUBLABRAL RECESS OF THE SUPERIOR GLENOID LABRUM - STUDY OF CADAVERS WITH CONVENTIONAL NONENHANCED MR-IMAGING, MR ARTHROGRAPHY, ANATOMIC DISSECTION, AND LIMITED HISTOLOGIC EXAMINATION

PURPOSE: To evaluate size, location, and appearance of the sublabral r ecess of the superior glenoid labrum, which mimics a superior labral t ear oriented in the anterior to posterior direction (SLAP) lesion with conventional magnetic resonance (MR) imaging, MR arthrography, gross dissection, and limited histologic evaluation. MATERIALS AND METHODS: Twenty-six cadaveric shoulder specimens that were freshly frozen were examined with nonenhanced MR imaging and with MR arthrography after in traarticular injection of dilute contrast material with gadolinium. In all specimens, the appearance of the superior glenolabral junction wa s categorized and was correlated to that seen at gross anatomic dissec tion. Histologic sections were obtained of two shoulders with large su blabral recesses in the plane of the MR sections. RESULTS: A sublabral recess was present in 19 (73%) shoulders and was deeper than 2 mm in 10 (39%). MR arthrography better demonstrated the sublabral recess tha n nonenhanced MR imaging. In 16 of 19 shoulders, the sublabral recess was located in the most anterior section obtained through the superior labrum. There was no definite correlation between subject age and sex and glenolabral junction type. At histologic examination of the two s houlders, a synovial lining of the sublabral recess was seen and there was no evidence of fibrosis to suggest a traumatic cause. CONCLUSION: A sublabral recess is common in cadaveric shoulders and has an appear ance similar to that of published examples of SLAP lesions. Histologic findings were consistent with normal anatomic structure rather than w ith acquired, posttraumatic lesions.