In the metatarsal lines, the tibial bowing of the bunion bulb is one of the symptoms of Down’s syndrome. People with Down’s syndrome have a special appearance: the distance between the eyes is wide, the outer corners of the eyes are upward slanted, the inner canthus is cumbersome, the ears are low, the bridge of the nose is low, the tongue is wide and thick, the mouth is often half-open or the tongue is protruding from outside of the mouth, the tongue surface has deep and many grooves, the palms of the hands are thick and short and thick, the last finger is short and small and is often curved inward or has two knuckles, and 40% of the affected patients have a pass-through palm. In the metatarsal lines, the tibial side of the bunion bulbous area is bowed, the spacing between the bunion and the second toe finger is large, and the joint ligaments are lax or seen to have low muscle tone. The causes of Down’s syndrome: I. Kernicterus Jaundice is also an important cause of Down’s syndrome, but now, due to advances in perinatal medicine, the proportion of Down’s syndrome caused by kernicterus jaundice has declined. Congenital anomalies include brain developmental abnormalities caused by various reasons, which can easily lead to Down’s syndrome. For example, congenital hydrocephalus caused by incomplete closure of the neural tube, total forebrain caused by the developmental disorder of vesicle evolution and flat gyrus malformation caused by the neurological tissue migration disorder, megacystic gyrus malformation, and small polymorphic gyrus, etc., including the lack of septum pellucidum caused by the joint obstacle or developmental hypoplasia. Cerebral hypoxia and ischemia Any obstacle that can cause blood circulation and gas exchange between the mother and the fetus, or lead to arterial hypotension or venous stasis in the newborn may cause cerebral hypoxia and ischemia, resulting in brain damage and cerebral palsy. The causes include: 1, mother’s factors: such as suffering from gestational hypertension syndrome, heart failure, hemorrhage, anemia, shock or drug abuse, drug overdose, etc.; 2, placental abnormalities: such as placental abruption, placenta praevia, placenta previa, placenta infarction, or placental dysfunction, etc.; 3, tape blood flow blockage; 4, such as tape prolapse, compression, knotting, or wrapping around the neck, etc.; 5, circulatory failure. Low-weight babies include premature immature babies and full-term babies. These infants have different degrees of intrauterine growth retardation. It also affects the development of central nervous system, and often complicates subventricular hemorrhage and intraventricular hemorrhage, the latter easily cause spastic bilateral paralysis. They are prone to Down’s syndrome.