The deltoid muscle has a dynamic activation to about 90–120 degrees of abduction. After that it has an almost static function the rest of the lift. The rest of the movement is mainly due to contraction of Trapezius muscle pars acendens, Serratus anterior muscle and trapezius pars decendens. They work together to tilt the Scapula to a position that makes the glenoid cavity point superiorly enabling the last degrees of abduction of the shoulder. Other contributing muscles include the Supraspinatus muscle and biceps brachii muscle caput longum. The rotator cuff is also active to pull the caput humeri into the glenoid cavity and counteract the superior forces of caput humeri created by the deltoid. The triceps contribute to the extension of the elbow, and counteract the force from biceps caput longum.