Body proportions

I am now fascinated by body proportions, I guess it has never occurred to me before how these change throughout childhood, I would have just said, "yea babies are all head when they are born and then that changes".... To be perfectly honest, I don't even know what the HC was of my other 2 kids, I am sure it was measured at the hospital, but it was never measured again and I certainly didn't take note of it. 

The length of my kids has never been measured either except at birth, I always just know what size clothes to get them when they are about to outgrow the previous set...


Anyhow, here is a little bit of what I have found out over the last few weeks.... 


The average length of a baby at birth, however, is 20 to 21 inches (50-53 cm). Most infants reach 1 ½ times their birth lengths (adding 9 to 10 inches) during the first year. 


Babies usually double their birthweight in four or five months and triple their birthweight by one year. - This I did know I have always been compulsive about weighing all my kids, to be more precise breastfed babies typically weight anywhere between 2.5 times to 3 times their bw by the age of 1. 

Now to the proportions.... Infants do not look like small adults.Their body proportions (relative size

of body parts) differ from those of adults. For example, an infant’s head is about one-fourth his or her total

length, while an adult’s head is one tenth of his or her total height (more like one eight according to some sites...). Unlike adults, the forehead of an infant is wider than the chin. 

From birth until six months, the infant’s head is larger than the chest. In most six-month-old children, the

chest becomes larger. The difference in the distance around the chest as compared to distance around the head continues to increase with age.

Besides having a large head, an infant has a long trunk, a “pot-bellied” abdomen, and short legs. The gain in

length during the first year is because the trunk grows. The legs do not grow much longer at this time. (I am not sure how true that is for Fiona, I have been measuring her legs and they certainly grew quite a bit).


The abdomen sticks out because the internal organs are large for the baby’s small body. Because the center of gravity is high on the baby’s body, the result is poor balance. No wonder babies toddle rather than walk!

At birth, the average infant weighs about seven pounds and is about 20 inches long. He will measure 24 inches three months later. By his first birthday he will typically be 30 inches in height, and by age two, 35 inches. An average girl will attain half her adult height before her second birthday. 
Target height for leg lengthening is the (fathers height + mothers height) divided by 2 and then - 7 which is 162 cm for Fi. This is the way a girl's projected height is calculated, I think it's plus/minus 7 or 8; of course our height is not determined by our parents' height to the last cm since then all siblings of the same sex would be the same height...

The different parts ol the body do not grow at the same rate, or at the same time. Instead, the head develops first, the torso next, and the limbs last. At birth a baby's head is about 25% of of the total body length, or about 60% of its adult size An adults head is normally less than 15% of the total body length. 


I never realized either that most of the head growth occurs by the age of 2, it is mind blowing if you think about it...

The torso develops next and is about one-half of its total length by the end of the second year. 
The legs and arms grow rapidly from the second year to the fourth year, at which time they are about one-halt their adult size. - I guess this explains why hypo is noticed by this time if not before... 


This progressive growth rate (head, trunk. legs) is called cephalocaudal development.

An infant's behavior, as well as body proportion reflects a cephalocaudal, head-to-trunk, direction of development. An infant's earliest and best organized behavior is the nursing or sucking response, which is a behavioral illustration of the fact that the head has the earliest growth increase . However, the sucking response is instinctive. The child s first purposeful behavior stems from the shoulder and pelvic girdles. The infant controls his head before his neck, his neck before his shoulders, and his shoulders before his trunk it is later in infancy that effective movements appear at the elbows, wrists, knees, and ankles.