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Effect of experimental suprascapular nerve block on active glenohumeral translations in vivo
Author(s) -
Werner Clément M. L.,
Weishaupt Dominik,
Blumenthal Stephan,
Curt Armin,
Favre Philippe,
Gerber Christian
Publication year - 2006
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.20011
Subject(s) - rotator cuff , suprascapular nerve , medicine , supraspinatus muscle , anatomy , paralysis , greater tuberosity , humerus , shoulder joint , tendon , surgery , brachial plexus
Static superior shoulder instability is associated with long‐standing rotator cuff tears. Factors or mechanisms which can prevent superior migration of the humeral head, and therefore allow preservation or restoration of shoulder function despite nonanatomical cuff repair, are poorly understood. The question has therefore arisen, whether centering of the humeral head was the result of active shoulder muscle function. It was the goal of this experimental investigation to (1) determine the pattern of glenohumeral translations during active shoulder abduction measured by open‐magnetic resonance imaging (MRI) techniques, and to (2) determine the influence of experimental paralysis of the infra‐ and supraspinatus muscles on these translations. In contrast to prior experimental investigations, the humeral head remained always centered in the glenoid fossa during active abduction. No superior migration of the humeral head could be provoked with experimental paralysis of the supra‐ and/or infraspinatus muscles. The hypothesis that static or dynamic superior humeral head displacement is prevented by active ‐supra‐ and/or infraspinatus muscle function must therefore be rejected, for the shoulder with a structurally intact muscle–tendon–bone unit. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:491–500, 2006