Anatomy and Function of the Tendon of the Long Head of the Biceps Muscle

This study reviews available information on the anatomy of the long head of the biceps tendon and its function in the shoulder. The tendon appears during the sixth to seventh week of gestation, and developmental anomalies in the form of absence or ectopic position have been described. The tendon has dual origin from the supraglenoid tubercle and glenoid labrum and courses toward the bicipital groove, protected by suspension sling in the rotator interval. The morphology of the bicipital groove has significant variability, affects the biomechanics of the tendon, and certain morphologic characteristics have been implicated in the development of bicipital tendinitis. Stability in the bicipital groove is inferred by the subscapularis tendon as well as the supraspinatus and coracohumeral ligament. The tendon has no avascular areas and contains sensory and sympathetic nerve fibers. Significant controversy exists regarding the exact function of the long head of the biceps tendon. The tendon depresses the humeral head in the glenoid and augments the stability of the glenohumeral joint. This role appears to be more prominent in the setting of a coexisting rotator cuff tear or shoulder instability.