Fin is 3 1/2 months old and is learning to hold a toy between his hands. He can tuck his chin and gaze at the toy in hands for a moment. Why is chin tuck considered an important early developmental milestone?
The three-month-old is discovering postural control in midline. One of the first stabilizing motions is the chin tuck. The baby is able to stabilize the head and trunk in midline and begin to touch his hands together over the chest. He will begin to spend moments looking down toward the hands as they are together. Chin tuck, otherwise known as capitol flexion, is the tilt of the head downward off the foundation of a stable cervical spine. When the baby becomes able to stabilize the cervical spine the sternocleidomastoid muscles activate to create capitol flexion. Over the next two months the baby’s ability to isolate and sustain chin tuck with downward visual gaze will become more developed. Core stability is characterized by a balance of flexion and extension. The chin tuck is the earliest example of this fine balance in the postural system.
The chin tuck position aligns and stabilizes the head, neck, jaw and tongue muscles to optimize sucking and swallowing. Chin tuck also stabilizes the visual system for midline organization.
in later development, downward visual gaze and chin tuck are important for standing alignment and balance. Capitol flexion is essential for downward visual gaze which we use for reading, writing, desk-work, crafts etc.