ABSTRACT
Warren (1983) and Garth et al. (1987) described throwers with symptoms of posterior shoulder pain by means of application of an external rotation force at 90° of abduction, but found no signs of instability. Walch et al. (1994) reported on arthroscopic cases with impaction of the deep surface of the supraspinatus tendon on the posterior-superior glenoid rim. Cadaveric research performed by Jobe and Sidles (1994) has shown that the rotator cuff pinched against the posterior-superior glenoid rim when the shoulder is positioned in maximum external rotation and abduction. Transection of specimens fixed in this position demonstrated the greater tuberosity forcing the rotator cuff and labrum against the glenoid rim. Davidson et al. (1995) termed this finding “internal impingement” relating it to a rotator cuff impingement mechanism. Jobe (1996) demonstrated that besides rotator cuff tendon, posterior glenoid impingement also may injure the superior labrum and/or the greater tuberosity.
