title: The superior capsule of the shoulder joint complements the insertion of the rotator cuff.
abstract: BACKGROUND
  To date, there are no studies about the attachment of the articular capsule of the superior shoulder joint. The aim of this study was to measure the width of the attachment of the articular capsule on the humerus, and to clarify the anatomy and the relationship to the footprint of the rotator cuff.
  
  
  METHODS
  The attachment of the articular capsule on the greater tuberosity was exposed. The width of the attachment of the capsule and the footprint of the rotator cuff were measured.
  
  
  RESULTS
  The maximum capsular width was located at the border between the infraspinatus and the teres minor, and measured 9.1 mm. The minimum capsular width was 3.5 mm, and it was located at 10.9 mm posterior to the anterior margin of the greater tuberosity and 1.5 mm anterior to the posterior margin of the supraspinatus.
  
  
  CONCLUSIONS
  Prior studies have overestimated the rotator cuff footprint width due to the lack of discrimination between the actual cuff insertion and capsule. The attachment of the articular capsule of the shoulder joint occupied a substantial area of the greater tuberosity. In particular, at the border between the infraspinatus and the teres minor, the very thick attachment of the articular capsule compensated for the lack of attachment of muscular components. The thinnest point of the articular capsule was 11 mm posterior to the anterior margin of the greater tuberosity and very close to the posterior edge of the tapered insertion of the supraspinatus, which could contribute to the etiology of degenerative rotator cuff tears.
authors.affiliation: Unit of Clinical Anatomy, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Akimoto
authors.initials: A
authors.lastname: Nimura
authors.forename: Atsuo
authors.initials: A
authors.lastname: Kato
authors.forename: Kumiko
authors.initials: K
authors.lastname: Yamaguchi
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Mochizuki
authors.forename: Atsushi
authors.initials: A
authors.lastname: Okawa
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sugaya
authors.forename: Keiichi
authors.initials: K
authors.lastname: Akita
mesh_terms: D000368:Aged; D002102:Cadaver; D005260:Female; D006801:Humans; D006811:Humerus / Q000033:anatomy & histology / Q000601:surgery; D017746:Joint Capsule / Q000033:anatomy & histology* / Q000601:surgery; D008297:Male; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000601:surgery; D017006:Rotator Cuff / Q000033:anatomy & histology / Q000601:surgery*; D012680:Sensitivity and Specificity; D012785:Shoulder Joint / Q000033:anatomy & histology* / Q000601:surgery