The scalenes muscles are located in the neck and help with neck movements and inspiration. The anterior scalene runs directly over the brachial plexus that gives nerve and blood supply to the arm. Poor neck and head posture as well as poor breathing mechanics can cause this muscle to become overloaded and develope trigger points. These points will refer pain into the shoulder, arm, and hand. As well as the shoulder blade. When tight, the anterior scalene muscle can put pressure on the brachial plexus causing numbness and tingling felt in the fingers and hand.