Vitamin D deficiency is mainly manifested in children's irritability and crying, sweating at night, restless sleep, baldness in the pillow, muscle relaxation and delayed development. Because of the low content of calcium and phosphorus in the bone, the epiphyseal cartilage proliferates excessively, the bones lack normal hardness, and the long bones often deform, forming "O" or "X" legs, also known as bowlegged legs; The knee swells to form a "locked knee"; The joint of ribs expands to form "ribbed beads"; Wrist and ankle are swollen, which is called rickets bracelet. Due to the softening of the skull, the head is deformed, and the frontal bone, parietal bone and occipital bone bulge outward, forming a "square head"; The edge of fontanel is soft, the bone seam is widened and the atresia is delayed; The sternum protrudes to form a "chicken breast"; The diaphragm pulls the softened ribs to form a depression, which is called "costal cartilage groove". In addition, more serious rickets may include hepatosplenomegaly and anemia.