Dynamic Glenohumeral Stability Provided by the Rotator Cuff Muscles in the Mid-Range and End-Range...

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Transcript of Dynamic Glenohumeral Stability Provided by the Rotator Cuff Muscles in the Mid-Range and End-Range...

Dynamic Glenohumeral Stability Provided by the Rotator Cuff Muscles in the Mid-Range and End-Range of Motion

by Seok-Beom Lee, Kyu-Jung Kim, Shawn W. O'Driscoll, Bernard F. Morrey, and Kai-Nan An

J Bone Joint Surg AmVolume 82(6):849-849

June 1, 2000

©2000 by The Journal of Bone and Joint Surgery, Inc.

Drawing showing the universal humeral positioner, with the humerus in 60 degrees of abduction and 45 degrees of extension with respect to the fixed scapula.

Seok-Beom Lee et al. J Bone Joint Surg Am 2000;82:849

©2000 by The Journal of Bone and Joint Surgery, Inc.

Photograph made after removal of the osteotomized glenoid, which was done to avoid contact between the humeral head and the glenoid during measurement of the force components.

Seok-Beom Lee et al. J Bone Joint Surg Am 2000;82:849

©2000 by The Journal of Bone and Joint Surgery, Inc.

Top-view photograph showing the force components generated by the rotator cuff muscles with the humerus in neutral rotation (representing the mid-range of motion) in the abducted and

extended shoulder.

Seok-Beom Lee et al. J Bone Joint Surg Am 2000;82:849

©2000 by The Journal of Bone and Joint Surgery, Inc.

Top-view photograph showing the force components generated by the rotator cuff muscles with the humerus in 90 degrees of external rotation (representing the end-range of motion) in the

abducted and extended shoulder.

Seok-Beom Lee et al. J Bone Joint Surg Am 2000;82:849

©2000 by The Journal of Bone and Joint Surgery, Inc.

Figs. 5-A, 5-B, and 5-C: Graphs showing the force components generated by the rotator cuff muscles in the abducted and extended shoulder as the humerus was rotated from neutral to 90

degrees of external rotation in intervals of 22.5 degrees.

Seok-Beom Lee et al. J Bone Joint Surg Am 2000;82:849

©2000 by The Journal of Bone and Joint Surgery, Inc.

Anterior-posterior shear force components.

Seok-Beom Lee et al. J Bone Joint Surg Am 2000;82:849

©2000 by The Journal of Bone and Joint Surgery, Inc.

Superior-inferior shear force components.

Seok-Beom Lee et al. J Bone Joint Surg Am 2000;82:849

©2000 by The Journal of Bone and Joint Surgery, Inc.