transverse cervical artery
The transverse cervical artery is one of the two arteries that arise (the other being the suprascapular artery), under cover of the sternomastoid, from a short, wide branch of the first part of the subclavian artery, called the thyrocervical trunk, which also gives off the inferior thyroid artery.
The transverse cervical artery crosses the scalenus anterior and the phrenic nerve, appears from under cover of the sternomastoid, and crosses the posterior triangle to end at the anterior border of the levator scapulae muscle by dividing into deep and superficial branches. In the posterior triangle, it is superficial to the upper trunks of the brachial plexus and the suprascapular nerve; and deep to the inferior belly of the omohyoid near the sternomastoid.
The superficial branch (superficial cervical artery) passes superficial to the levator scapulae, and ramifies on the deep surface of the trapezius. The deep branch (descending scapular artery) runs downwards deep to the levator and the rhomboids, along the medial margin of the scapula; it may arise directly from the third part of the subclavian.