Using abduction and external rotation of the shoulder to increase the sensitivity of MR arthrography in revealing tears of the anterior glenoid labrum.

10 Cvitanic O, Tirman PF, Feller JF, Bost FW, Minter J, Carroll KW.

Posterosuperior glenoid impingement of the shoulder: findings at MR imaging and MR arthrography with arthroscopic correlation.

9 Tirman PF, Bost FW, Garvin GJ, et al.

MRI of internal impingement of the shoulder. Internal impingement: findings on magnetic resonance imaging and arthroscopic evaluation.

7 Kaplan LD, McMahon PJ, Towers J, Irrgang JJ, Rodosky MW.

Shoulder instability and impingement in throwing athletes. Impingement of the deep surface of the supraspinatus tendon on the posterosuperior glenoid rim: an arthoscopic study.

5 Walch G, Boileau P, Noel E, Donell ST.

Internal impingement in the shoulder of the overhand athlete: pathophysiology, diagnosis, and treatment. Internal impingement of the shoulder: a clinical and arthroscopic analysis.

3 McFarland EG, Hsu CY, Neira C, O'Neil O.

Superior glenoid impingement: current concepts. Advances in the understanding of throwing injuries of the shoulder. Distances between the rotator cuff insertion sites and the glenoid decreased in the loaded ABER position. 01).Ĭonclusion: The unloaded and loaded ABER positions resulted in contact of the supraspinatus and infraspinatus with the glenoid in all volunteers. Supraspinatus tendon to glenoid and infraspinatus tendon to glenoid minimum distances also decreased significantly ( P <. The minimum distance between the supraspinatus insertion and acromion in the loaded ABER position decreased significantly ( P <. Deformation of the infraspinatus on the glenoid was seen in four volunteers, whereas supraspinatus deformation was only seen in one volunteer.

In the loaded ABER position, contact was also observed between the infraspinatus and supraspinatus and the posterior and posterosuperior glenoid, respectively. Results: In the unloaded ABER position, contact was seen between the infraspinatus and supraspinatus tendons and the glenoid in all eight volunteers. Minimum distances were compared by using a paired Student t test.

Minimum distances were computed between the tendon insertion sites and the glenoid, acromion, and coracoid for the loaded ABER position. Three-dimensional anatomic models generated from the MR images were used to measure distances. Two radiologists graded rotator cuff contact on a three-point scale. Volunteers were imaged in an unloaded ABER position with the arm at 90° abduction and in a loaded ABER position, with a 1-kg load that produced an average external rotation of 111° ± 6 (standard deviation). Eight male volunteers with no history of shoulder pain or pathology were imaged in a 0.5-T open MR imager. Materials and Methods: The study was institutional review board approved and HIPAA compliant, and informed consent was received. Purpose: To prospectively evaluate rotator cuff contact with the glenoid in healthy volunteers placed in the unloaded and loaded abduction and external rotation (ABER) positions in an open magnetic resonance (MR) imager.

Abduction of shoulder