title: Cross-sectional area of the tendon and the muscle of the biceps brachii in shoulders with rotator cuff tears: a study of 14 cadaveric shoulders.
abstract: BACKGROUND
  The intraarticular portion of the long head of the biceps tendon is often widened in shoulders with cuff tears. It is unclear whether this is a local phenomen or is caused by muscle hypertrophy.
  
  
  METHODS
  We investigated morphological changes of the biceps brachii in 14 embalmed shoulders: 7 with intact rotator cuff and 7 with rotator cuff tears. We measured the cross-sectional area (CSA) of the tendon of the long head of the biceps (LHB) at 9 levels between the glenoid origin and the musculotendinous junction. The muscle volume and the muscle fiber length of the long and short heads of the biceps were measured to calculate the physiological CSA (PCSA) by dividing the volume by the fiber length.
  
  
  RESULTS
  The CSA of the LHB tendon at the entrance to the bicipital groove was greater in cuff tear shoulders than in normal shoulders. The PCSA of the biceps was similar in normal and cuff tear shoulders.
  
  
  CONCLUSIONS
  Hypertrophy of the LHB tendon appears to be a localized morphological change near the entrance to the bicipital groove.
authors.affiliation: Department of Orthopedic Surgery, Akita University School of Medicine, Japan. ai@doc-med.akita-u.ac.jp
authors.forename: Aizawa
authors.initials: A
authors.lastname: Toshiaki
authors.forename: Eiji
authors.initials: E
authors.lastname: Itoi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Minagawa
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Yamamoto
authors.forename: Yilihamu
authors.initials: Y
authors.lastname: Tuoheti
authors.forename: Nobutoshi
authors.initials: N
authors.lastname: Seki
authors.forename: Kyoji
authors.initials: K
authors.lastname: Okada
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Shimada
mesh_terms: D000368:Aged; D002102:Cadaver; D006801:Humans; D006984:Hypertrophy; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology; D017006:Rotator Cuff / Q000473:pathology*; D000070636:Rotator Cuff Injuries; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000473:pathology*; D013710:Tendons / Q000473:pathology