A newborn, when lifted from a supine position by its arms, will not be able to hold its head up. The head flops back in what is commonly referred to as “head lag.” This is entirely normal for a brand new baby, and almost everyone assumes this is the result of the baby not yet having had an opportunity to develop strength in his or her neck muscles.
By the age of three or four months, however, a naturally developing infant will be able to bring the head up in line with the body. It is commonly believed that the baby has now developed the requisite neck strength to bring the head up, but, in fact, something far more “global” is taking place here. Continue reading