In a study of 67 shoulders evaluated by axillary arthrotomography, tears of the glenoid labrum were accurately detected in all 26 surgically confirmed cases. One false-positive case was identified in the five patients without labral tears; there were no false-negative cases. Only 40% of the patients had clinical evidence of subluxation or dislocation. Axillary arthrotomography provides important information about the integrity of the labrum that may be helpful in planning surgery for patients with anatomic instability. Its greatest utility seems to be in those patients without clinical subluxation or dislocation but with pain, clicking, or vague shoulder discomfort secondary to labral pathology (functional instability). In these patients, the arthrotomogram forms the basis for surgical intervention.