Background: Posterior shoulder tightness has been proposed to contribute to or cause a myriad of shoulder conditions. The tightness of the posteroinferior capsule and the teres minor and infraspinatus muscles of the posterior cuff has been hypothesized to cause osteokinematic [e. g. https://www.roneverhart.com/Straight-Blade-Receptacles-Duplex-2P-3W-20A-125V-5-20R-WHITE-HUBBELL-5362W/