Final answer:
The suprascapular nerve, artery, and vein can be found in the suprascapular notch of the scapula before supplying the supraspinatus and infraspinatus muscles.
Step-by-step explanation:
The suprascapular nerve, artery, and vein can be found before they supply the supraspinatus and infraspinatus in the suprascapular notch of the scapula. The suprascapular notch is located on the superior border of the scapula. It is a passageway for these structures to reach the muscles of the shoulder.