The developmental sequence of turning: 3 months of age: desire to turn over; 5.8 months of age: turning from prone to supine; 6 months of age: hand support, lifting head and chest at least 90°; turning from supine to prone; purpose: to promote the completion of trunk gyration; to promote the disappearance of asymmetrical postures; significance: the trunk upright reflex can only appear when turning is completed; the flexion and support movements of the femoral and knee joints can only be completed; the developmental process of turning: 1. 1. cervical upright reflexes; (the development of turning is mostly stagnant at 1 or 2, due to residual primitive reflexes, immature uprightness and balance at the midbrain and cortical levels.) 2. dorsiflexion of the head and coracoelasticity; 3. automatic turning; 4. purposeful turning.