Morphology of the humeral insertion of the supraspinatus and infraspinatus tendons: Application to rotator cuff repair.

In shoulder surgery, a precise understanding of anatomical relationships is required for accurate reconstruction. Reports in recent literature have challenged the traditional definitions of the humeral footprints of the supraspinatus and infraspinatus tendons. This study aims to precisely delineate these footprints. The rotator cuffs of 54 shoulders from 27 Australian Caucasoid donor cadavers were examined. The tendinous portions were dissected down to their region/footprint of attachment upon the humerus. Measurements of those footprints, upon the greater and lesser tuberosities, were made. Those measurements were statistically analyzed for any association with age, sex, height, or side. Twenty-seven cadavers had an average age at death of 74.9 (± 12.8), 56% were male, average height was 168 (± 8.6) cm. Due to premorbid fracture, or degeneration, 11 shoulders were excluded. The footprint of the supraspinatus was triangular, with a medial, anteroposterior length of 20.4 ± 4.2 mm. Its lateral anteroposterior length was 6.3 ± 1.6 mm and its maximal mediolateral width was 6.6 ± 2.7 mm. Its calculated area was 122.0 ± 66.6 mm(2). The footprint of the infraspinatus was trapezoidal, with a medial anteroposterior length 22.6 ± 3.0 mm. Its lateral anteroposterior length was 25.4 ± 3.3mm and its maximal mediolateral width was 12.0 ± 2.7 mm. Its calculated area was 294.9 ± 74.1 mm(2). There was no statistical correlation between size of the footprint and age, sex, side, or height. The humeral footprints of the supraspinatus and infraspinatus tendons upon the greater tuberosity were distinct. The lateral border of the infraspinatus' humeral attachment extended much farther anteriorly upon the highest facet of the greater tuberosity than in traditional descriptions.