Liver governs the sinews

From The Magic Pivot (灵枢 líng shū, jiǔ zhēn lùn). The sinews (tendons, muscles; see sinew) are dependent on the liver. The liver governs the sinews means essentially the same as the liver governs physical movement. Only when liver blood is abundant can their nourishing influence reach the sinews and enable them to move normally. If liver blood is insufficient, the resulting failure of the blood to nourish the sinews adequately brings on hypertonicity (tension and stiffness) or numbness in the limbs, with difficulty in bending and stretching. When liver wind stirs internally, tremors, convulsions, and arched-back rigidity are observed.