Rickets, also known as nutritional vitamin D deficiency rickets, is a chronic nutritional disease in children caused by inadequate vitamin D in their bodies, leading to disorders in calcium and phosphorus metabolism and characterized by changes in the growth plates. Its manifestation varies with different ages. In infants under six months, especially those under three months, symptoms often include increased nervous excitability, such as being easily irritable, restless, sweating, and shaking their heads due to scalp irritation. As the condition progresses in children under six months, the primary changes are seen in the skull; the edges of the anterior fontanelle are softer, and the skull is thinner. After six months, the softening of the skull disappears, but there can be ping-pong ball-like changes around the skull, leading to a box-shaped head from seven to eight months. Gradually, beading changes form, most notably around the 7th to 10th ribs. Around the age of one, children can develop a pigeon chest deformity, and in severe cases of rickets, a horizontal depression forms at the lower edge of the thoracic cage, known as the costal groove or Harrison's groove. Due to bone softening and muscle and joint laxity, when the child begins to stand and walk, the legs may become bow-legged or X-shaped, and in severe cases, can develop into 'K'-shaped leg deformities. Once the child starts to sit and stand, general ligament laxity can cause spinal deformities. Severe hypophosphatemia leads to muscle carbohydrate metabolism disorder, resulting in overall muscle laxity, decreased muscle tone, and subsequently reduced muscle strength.