Final answer:
If the shoulder is abducted to 150 degrees, approximately 50 degrees of scapular upward rotation has occurred, as part of the scapulohumeral rhythm which coordinates the shoulder girdle and humerus movements.
Step-by-step explanation:
During upper limb abduction, the scapula undergoes a superior rotation, which allows the glenoid cavity to move upward, aiding in lifting the arm higher without obstruction from the acromion of the scapula. The scapulohumeral rhythm is the coordinated movement between the shoulder girdle and the humerus. Typically, for every 2 degrees of shoulder abduction, there is 1 degree of scapular rotation. Therefore, if the shoulder is abducted to 150 degrees, approximately 50 degrees of upward rotation of the scapula has occurred. This rotation is crucial for providing the clearance needed for full range of abduction and is influenced by the combined action of muscles around the scapula.