Superior labrum anterior and posterior lesions and microinstability

The glenohumeral joint provides the greatest range of motion of any joint in the human body. Over the past several decades, histologic studies, biomechanical studies, and improved arthroscopic techniques have contributed to improved knowledge and treatment of glenohumeral joint abnormalities. Continuing advances in magnetic resonance technology have allowed for improved noninvasive visualization of the stabilizers of the shoulder. This article reviews the concept of glenohumeral joint microinstability and its relationship with superior labrum anterior and posterior (SLAP) lesions, reviews the role of the labrum as a stabilizer of the shoulder, and focuses on the diagnosis and classification of SLAP lesions.