Shoulder Biomechanics Part Two (Kinetic Control)

-The lower trapezius is innervated by the spinal accessory nerve (C1-6). Whereas the latissimus dorsi muscle is innervated by the thoracodorsal nerve (C6-8). -In a C6 tetraplegic (quadriplegic) patient, it indicates that C6 and segments above (C1–C6) are intact, but roots below C6 (C7–S5) are affected. Although the latissimus dorsi is weak and the lower trapezius remains functionally intact, these muscles alone cannot produce a full lift. Instead, compensatory mechanisms enable a partial weight lift or pressure relief.