Posture has long been thought of in terms of standing and sitting, and correct posture as the erect position assumed when one is under inspection, but posture should really be considered as the sum total of the positions and movements of the body throughout the day and throughout life. It should include not only the fundamental static positions in lying, sitting and standing and the variations of these positions but also the dynamic postures of the body in motion or in action, for it is here that posture becomes most important and most effective. Posture has a direct relation to the comfort, mechanical efficiency and physiologic functioning of the individual.
DEVELOPMENT OF POSTURE
The Baby's Posture.—
The posture of the newborn baby is quite different from that of the adult or even that of the older child. The whole spine and trunk as well as the hips, knees and ankles
HOWORTH B. DYNAMIC POSTURE. JAMA. 1946;131(17):1398–1404. doi:10.1001/jama.1946.02870340004002