Trapezius

O - Occipital bone, ligamentum nuchae, spine of seventh cervical vertebra, spines of all thoracic vertebrae I - Upper fibers into lateral third of clavicle; middle and lower fibers into acromion and spine of scapula N - Spinal part of accessory nerve (motor) and C3 and 4 (sensory) A - Upper fibers elevate the scapula; middle fibers pull scapula medially; lower fibers pull medial border of scapula downward