Observe the routine of subclavian a. its neighbouring Left right subclavian a from different origin the arteries both side locate the back of the sternoclavicular joint scalenus anterior. it is divided into 3 portions by scalenus anterior nferior 6 Middle scalene m thyroid a. vertebral a Transverse cervical a Dorsal scapular a thoracic duct he brachi recurrent subclavian a vagus n Common carotid artery (reflected) Vagus nerve(reflected) Left intemal jugularObserve the routine of subclavian a.& its neighbouring Left & right subclavian a.from different origin.the arteries both side locate the back of the sternoclavicular joint & scalenus anterior.it is divided into 3 portions by scalenus anterior