bones 1

The tendon of scalene anterior inserts in the inner portion of the curve of the first rib, toward the front. There are grooves on the top of the first rib in front and in back of the scalene tubercle for the passage of the subclavian artery and vein. The middle scalene inserts on a broader area on the top of the first rib more posteriorly. The brachial plexus travels between the anterior and middle scalenes, surrounding the subclavian artery.