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Symmetrical tonic neck reflex

The symmetric tonic neck reflex normally appears and develops around 6–9 months of age and should integrate by around 12 months. When the child's head flexes forward, extending the back of the neck, the upper extremities will contract and the lower extremities will extend. Conversely, when the child's head is extended backward, contracting the back of the neck, the upper extremities will extend and the lower extremities will contract. This reflex is important to help a child push up onto their hands and knees but may inhibit actual forward creeping or crawling if it is not properly integrated. If this reflex is retained beyond 2–3 years, it may result, directly or indirectly, in a range of physical and neurological developmental delays.