Reply to: “The superior capsule of the shoulder joint complements the insertion of the rotator cuff”

Abstract

We appreciate the opportunity to respond to the letter to the editor. Together, the letter and our reply may provide enhanced understanding of the structure and significance of the humeral-side attachment of the superior glenohumeral capsule. In a previous article, we first described that the attachment of the articular capsule of the shoulder joint at the anterior and posterior part was thicker than had been previously described.6Nimura A. Kato A. Yamaguchi K. Mochizuki T. Okawa A. Sugaya H. et al.The superior capsule of the shoulder joint complements the insertion of the rotator cuff.J Shoulder Elbow Surg. 2012; 21: 867-872https://doi.org/10.1016/j.jse.2011.04.034Abstract Full Text Full Text PDF PubMed Scopus (116) Google Scholar Additionally, the thinnest point of the attachment was about 11 mm posterior to the anterior-medial edge of the greater tuberosity. Although only the attachment site of the superior capsule was analyzed in detail, we regret that the anatomy of the midsubstance was not discussed in our recent publication, as the letter indicated.Burkhart et al1Burkhart S.S. Esch J.C. Jolson R.S. The rotator crescent and rotator cable: an anatomic description of the shoulder's “suspension bridge.”.Arthroscopy. 1993; 9: 611-616Abstract Full Text PDF PubMed Scopus (294) Google Scholar described the details of the rotator cable-crescent structure. They referred to the rotator crescent as the thin, crescent-shaped area of rotator cuff and capsule including the supraspinatus and infraspinatus and to the rotator cable as the relatively thick bundle surrounding the rotator crescent. The average anteroposterior diameter of the rotator crescent was reported to be 41.35 mm. This is approximately the anteroposterior width of the medial margin of the supraspinatus and infraspinatus in the report of Mochizuki et al.5Mochizuki T. Sugaya H. Uomizu M. Maeda K. Matsuki K. Sekiya I. et al.Humeral insertion of the supraspinatus and infraspinatus. New anatomical findings regarding the footprint of the rotator cuff.J Bone Joint Surg Am. 2008; 90: 962-969https://doi.org/10.2106/JBJS.G.00427Crossref PubMed Scopus (205) Google Scholar On the basis of such findings, the anterior and posterior thick attachments of the superior capsule are speculated to be the insertion of the rotator cable structure, with the thinnest attachment corresponding to the rotator crescent.In addition, Burkhart et al1Burkhart S.S. Esch J.C. Jolson R.S. The rotator crescent and rotator cable: an anatomic description of the shoulder's “suspension bridge.”.Arthroscopy. 1993; 9: 611-616Abstract Full Text PDF PubMed Scopus (294) Google Scholar functionally proposed that these structures act as a suspension bridge where the torn end of the cuff corresponds to the cable and that the anterior and posterior healthy insertion of the cuff correspond to the pole that holds up the bridge cable. Halder et al4Halder A.M. O'Driscoll S.W. Heers G. Mura N. Zobitz M.E. An K.N. et al.Biomechanical comparison of effects of supraspinatus tendon detachments, tendon defects, and muscle retractions.J Bone Joint Surg Am. 2002; 84: 780-785PubMed Google Scholar studied the biomechanics of these structures and described that the forces of the rotator cuff could be transmitted effectively in small-sized and medium-sized rotator cuff tears because the rotator cable structures are maintained. If these structures correspond to the anterior and posterior thick attachment of the superior capsule, they might increasingly enhance the significance of the capsule attachment.Clark and Harryman2Clark J.M. Harryman 2nd, D.T. Tendons, ligaments, and capsule of the rotator cuff. Gross and microscopic anatomy.J Bone Joint Surg Am. 1992; 74: 713-725Crossref PubMed Scopus (532) Google Scholar stated that the coracohumeral ligament is interposed between the supraspinatus tendon and the capsule structure. In addition, Edelson et al3Edelson J.G. Taitz C. Grishkan A. The coracohumeral ligament. Anatomy of a substantial but neglected structure.J Bone Joint Surg Br. 1991; 73: 150-153PubMed Google Scholar described that the coracohumeral ligament is the thickened fibrous capsule of the shoulder joint. At the anterior border of the supraspinatus, the coracohumeral ligament and the superior capsule are intermingled and together envelop the anterior edge of the supraspinatus and then attach to the anterior border of the greater tuberosity. Therefore, the thicker attachment of the superior capsule, based on our concept, was thought to correspond to these intermingled structures.Regarding the posterior part of the superior capsule, Pouliart et al7Pouliart N. Somers K. Eid S. Gagey O. Variations in the superior capsuloligamentous complex and description of a new ligament.J Shoulder Elbow Surg. 2007; 16: 821-836https://doi.org/10.1016/j.jse.2007.02.138Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar reported the presence of the fibrous band composed of parallel collagen fibers and proposed the term “posterosuperior glenohumeral ligament.” They described that the attachment of these structures is marked by the bony irregularities on the posterior glenoid neck and that together they may act as a substantial fibrous structure against tension and stress. The thickest attachment of the posterosuperior capsule in our report, which compensated for the deficient area of the infraspinatus and teres minor, could be identical to this structure. We appreciate the opportunity to respond to the letter to the editor. Together, the letter and our reply may provide enhanced understanding of the structure and significance of the humeral-side attachment of the superior glenohumeral capsule. In a previous article, we first described that the attachment of the articular capsule of the shoulder joint at the anterior and posterior part was thicker than had been previously described.6Nimura A. Kato A. Yamaguchi K. Mochizuki T. Okawa A. Sugaya H. et al.The superior capsule of the shoulder joint complements the insertion of the rotator cuff.J Shoulder Elbow Surg. 2012; 21: 867-872https://doi.org/10.1016/j.jse.2011.04.034Abstract Full Text Full Text PDF PubMed Scopus (116) Google Scholar Additionally, the thinnest point of the attachment was about 11 mm posterior to the anterior-medial edge of the greater tuberosity. Although only the attachment site of the superior capsule was analyzed in detail, we regret that the anatomy of the midsubstance was not discussed in our recent publication, as the letter indicated. Burkhart et al1Burkhart S.S. Esch J.C. Jolson R.S. The rotator crescent and rotator cable: an anatomic description of the shoulder's “suspension bridge.”.Arthroscopy. 1993; 9: 611-616Abstract Full Text PDF PubMed Scopus (294) Google Scholar described the details of the rotator cable-crescent structure. They referred to the rotator crescent as the thin, crescent-shaped area of rotator cuff and capsule including the supraspinatus and infraspinatus and to the rotator cable as the relatively thick bundle surrounding the rotator crescent. The average anteroposterior diameter of the rotator crescent was reported to be 41.35 mm. This is approximately the anteroposterior width of the medial margin of the supraspinatus and infraspinatus in the report of Mochizuki et al.5Mochizuki T. Sugaya H. Uomizu M. Maeda K. Matsuki K. Sekiya I. et al.Humeral insertion of the supraspinatus and infraspinatus. New anatomical findings regarding the footprint of the rotator cuff.J Bone Joint Surg Am. 2008; 90: 962-969https://doi.org/10.2106/JBJS.G.00427Crossref PubMed Scopus (205) Google Scholar On the basis of such findings, the anterior and posterior thick attachments of the superior capsule are speculated to be the insertion of the rotator cable structure, with the thinnest attachment corresponding to the rotator crescent. In addition, Burkhart et al1Burkhart S.S. Esch J.C. Jolson R.S. The rotator crescent and rotator cable: an anatomic description of the shoulder's “suspension bridge.”.Arthroscopy. 1993; 9: 611-616Abstract Full Text PDF PubMed Scopus (294) Google Scholar functionally proposed that these structures act as a suspension bridge where the torn end of the cuff corresponds to the cable and that the anterior and posterior healthy insertion of the cuff correspond to the pole that holds up the bridge cable. Halder et al4Halder A.M. O'Driscoll S.W. Heers G. Mura N. Zobitz M.E. An K.N. et al.Biomechanical comparison of effects of supraspinatus tendon detachments, tendon defects, and muscle retractions.J Bone Joint Surg Am. 2002; 84: 780-785PubMed Google Scholar studied the biomechanics of these structures and described that the forces of the rotator cuff could be transmitted effectively in small-sized and medium-sized rotator cuff tears because the rotator cable structures are maintained. If these structures correspond to the anterior and posterior thick attachment of the superior capsule, they might increasingly enhance the significance of the capsule attachment. Clark and Harryman2Clark J.M. Harryman 2nd, D.T. Tendons, ligaments, and capsule of the rotator cuff. Gross and microscopic anatomy.J Bone Joint Surg Am. 1992; 74: 713-725Crossref PubMed Scopus (532) Google Scholar stated that the coracohumeral ligament is interposed between the supraspinatus tendon and the capsule structure. In addition, Edelson et al3Edelson J.G. Taitz C. Grishkan A. The coracohumeral ligament. Anatomy of a substantial but neglected structure.J Bone Joint Surg Br. 1991; 73: 150-153PubMed Google Scholar described that the coracohumeral ligament is the thickened fibrous capsule of the shoulder joint. At the anterior border of the supraspinatus, the coracohumeral ligament and the superior capsule are intermingled and together envelop the anterior edge of the supraspinatus and then attach to the anterior border of the greater tuberosity. Therefore, the thicker attachment of the superior capsule, based on our concept, was thought to correspond to these intermingled structures. Regarding the posterior part of the superior capsule, Pouliart et al7Pouliart N. Somers K. Eid S. Gagey O. Variations in the superior capsuloligamentous complex and description of a new ligament.J Shoulder Elbow Surg. 2007; 16: 821-836https://doi.org/10.1016/j.jse.2007.02.138Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar reported the presence of the fibrous band composed of parallel collagen fibers and proposed the term “posterosuperior glenohumeral ligament.” They described that the attachment of these structures is marked by the bony irregularities on the posterior glenoid neck and that together they may act as a substantial fibrous structure against tension and stress. The thickest attachment of the posterosuperior capsule in our report, which compensated for the deficient area of the infraspinatus and teres minor, could be identical to this structure. Regarding “The superior capsule of the shoulder joint complements the insertion of the rotator cuff”Journal of Shoulder and Elbow SurgeryVol. 22Issue 2PreviewI read the article by Nimura et al4 with great interest and congratulate the authors on their excellent dissections and beautiful illustrations. This work adds another important element to the growing body of knowledge concerning the interplay between the rotator cuff and the (superior) glenohumeral capsule. I wish to point out an oversight, however. Full-Text PDF