The scalene muscle group (anterior,middle, and posterior) is located in the anterolateral portion of the neck. The muscles originate from the transverse processes of the cervicle vertebrae; to insert on the first 2 ribs. Together the scalene muscles act to elevate the upper 2 ribs and flex the neck. The anterior and the middle scalene muscles can serve as a landmark for the brachial plexus, because the brachial plexus courses between them. 2 other prominent groups of muscles are the erector spinae and the transverse spinal.