The Rotator Cuff Footprint: A Cadaveric Study of the Morphometry and Morphology

The musculotendinous hood of the rotator cuff muscle complex is formed by four tendons which thicken and merge with the underlying glenohumeral capsule as they insert onto the respective regions of the humeral head. This insertional anatomy has been reported to exhibit several pathological patterns which serve as the basis for the operative repair of cuff tears. Since previous literature concentrated on macro-evaluations of tears specific to the supraspinatus tendon, the present study aimed to investigate the macromorphological and morphometric parameters of all four rotator cuff tendons. Observation of the insertion site configurations and computation of the relative tendon morphometry were performed once the glenohumeral region in forty adult cadaveric specimens (n=80) were bilaterally dissected. Statistical analysis also reflected the demographic representation of the sample: (Age: 74.83±12.92 years old; Gender: 24 Males, 16 Females; Race: 38 White, 2 Black). The general mean supero-inferior and medio-lateral distances were recorded specific to the entire rotator cuff and each tendinous insertion site as follows: i) Subscapularis: 22.57±3.13 mm, 20.45±4.79 mm; ii) Supraspinatus: 15.20±4.29 mm, 20.14±5.38 mm; iii) Infraspinatus: 19.49±5.21 mm, 19.07±4.74 mm; iv) Teres minor: 19.02±5.21 mm, 15.33±3.75 mm; v) Entire rotator cuff: 76.28±10.57 mm, 75.18±11.41mm. Although variation in insertion configurations existed, predominant shapes were identified: Subscapularis – Oval (72.5 %), Supraspinatus Rectangular (76.3 %), Infraspinatus Oval (78.8 %), Teres minor Round (100 %). In view of the statistically significant P values, it may be postulated that knowledge of the superoinferior and medio-lateral distances may provide dimensional data required to obtain optimal cuff coverage during reconstruction procedures. Furthermore, the variation in the insertion patterns may indicate the progression of rotator tendon tears.