title: Histologic and biomechanical characteristics of the supraspinatus tendon: Reference to rotator cuff tearing.
abstract: A bursal- or joint-side incomplete thickness tearing of the rotator cuff is clinically important, because it is known that this tearing has the potential to develop into a complete tendon disruption. Normal cadaveric supraspinatus tendons were analyzed histologically and biomechanically to clarify the differences in pathomechanical causation of bursal- and joint-side incomplete tears. Histologically, the bursal-side layer was composed of tendon bundles with a decreasing muscular component toward the insertion. The joint-side layer was a complex of tendon, ligament, and joint capsule without transitional areas. Biomechanically, the bursal-side layer had greater deformation and tensile strength. When each layer was divided into three portions of equal length, the middle segment of the bursal-side layer elongated the most, whereas the entire joint-side layer increased evenly in length. We conclude that the joint-side layer is more vulnerable to a tensile load than the bursal-side layer.
authors.affiliation: From the Department of Orthopaedic Surgery, School of Medicine, Tokai University, Kanagawa, Japan; Department of Orthopaedic Surgery, School of Medicine, Keio University, Tokyo Japan.
authors.forename: T
authors.initials: T
authors.lastname: Nakajima
authors.forename: N
authors.initials: N
authors.lastname: Rokuuma
authors.forename: K
authors.initials: K
authors.lastname: Hamada
authors.forename: T
authors.initials: T
authors.lastname: Tomatsu
authors.forename: H
authors.initials: H
authors.lastname: Fukuda