The lateral cervical region (also known as the posterior triangle of the neck) contains important structures that connect the head and visceral neck to the arm and thorax. Several layers of important fascia surround and define the triangle. Muscles related to this triangle are responsible for neck flexion, head rotation, head extension, and movements about the shoulder girdle. Many terminal portions of neurovascular bundles cross through it on their way to/from more distal targets of the neck and shoulder muscles and skin. Lymphatic drainage returns to the venous system in this area.