title: The aponeurotic expansion of the supraspinatus tendon: anatomy and prevalence in a series of 150 shoulder MRIs.
abstract: OBJECTIVE
  To describe the aponeurotic expansion of the supraspinatus tendon with anatomic correlations and determine its prevalence in a series of patients imaged with MRI.
  
  
  METHODS
  In the first part of this HIPAA-compliant and IRB-approved study, we retrospectively reviewed 150 consecutive MRI studies of the shoulder obtained on a 1.5-T system. The aponeurotic expansion at the level of the bicipital groove was classified as: not visualized (type 0), flat-shaped (type 1), oval-shaped and less than 50% the size of the adjacent long head of the biceps section (type 2A), or oval-shaped and more than 50% the size of the adjacent long head of the biceps section (type 2B). In the second part of this study, we examined both shoulders of 25 cadavers with ultrasound. When aponeurotic expansion was seen at US, a dissection was performed to characterize its origin and termination.
  
  
  RESULTS
  An aponeurotic expansion of the supraspinatus located anterior and lateral to the long head of the biceps in its groove was clearly demonstrated in 49% of the shoulders with MRI. According to our classification, its shape was type 1 in 35%, type 2A in 10 % and type 2B in 4%. This structure was also identified in 28 of 50 cadaveric shoulders with ultrasound and confirmed at dissection in 10 cadavers (20 shoulders). This structure originated from the most anterior and superficial aspect of the supraspinatus tendon and inserted distally on the pectoralis major tendon.
  
  
  CONCLUSIONS
  The aponeurotic expansion of the supraspinatus tendon can be identified with MRI or ultrasound in about half of the shoulders. It courses anteriorly and laterally to the long head of the biceps tendon, outside its synovial sheath.
authors.affiliation: Department of Radiology and Research Center, Centre Hospitalier de l'Université de Montréal, Montréal, QC, Canada, thomas.moser@umontreal.ca.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Moser
authors.forename: Étienne
authors.initials: É
authors.lastname: Cardinal
authors.forename: Nathalie J
authors.initials: NJ
authors.lastname: Bureau
authors.forename: Raphaël
authors.initials: R
authors.lastname: Guillin
authors.forename: Pascale
authors.initials: P
authors.lastname: Lanneville
authors.forename: Detlev
authors.initials: D
authors.lastname: Grabs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012785:Shoulder Joint / Q000002:abnormalities* / Q000473:pathology*; D013710:Tendons / Q000002:abnormalities* / Q000473:pathology*; D055815:Young Adult