Posted by: ainsleyjason | February 3, 2010

Babies spine development

Spine Development in an Infant

Our spine is not perfectly straight, even though it may appear so when looking at someone from the front or the back. When you look at a person from the side four slight curves are visible forming an elongated “S” shape. These curves help keep us flexible and balanced. They also help to absorb stresses placed on our bodies through daily activities that impact our spine like walking, running and jumping. We weren’t born with these curves. Normal curves of the spine develop gradually. “They are formed as a consequence of adaptation to the external environment (gravity)”(Morningstar, 2005). At birth, babies are in a state of flexion, still curled up, with their spine in a natural long c-shaped (convex) curve. At first, a baby does not have the strength to hold his head up, nor the balancing curves in his spine to do so. But gradually as the muscles in his neck get stronger, he begins to lift his heavy head against gravity, and a curve starts to develop in his neck (the cervical curve) to help balance his head. When your baby starts to creep and crawl the lower back (lumbar curve) and the muscles that support it develop. Only by about the first year does your baby attain these curves in his spine(Leveau,1877).

Laying flat is Stressful on Spine and Hips

As shown above an infant’s c-shaped spine doesn’t stretch out immediately after birth. On the contrary, the s-shape of the spine is not fully developed until he starts to walk on his own. Laying your young infant flat on his back is not gentle on his spine. In fact, it is stretching the c-curved spine into a straight line. It is actually stressing the infant’s spine instead of supporting it’s natural shape. Research shows that keeping an infants spine straight is not a sound physiological position. In addition to stressing the baby’s spine it can negatively influence the development of your baby’s hip joints (Kirkilionis, 2002).

Existence in Containers

This does not mean that laying flat for a couple of walks around the block in a stroller is going to reek havoc on your baby’s physical development. But the truth is that the average Western infant between three weeks and three months of age is carried a little more than two and a half hours a day(Heller, 118.) We end up carrying the baby to the car in a container, through the store in a container, to eat lunch in a container, back to the car in a container and home in a container* sometimes to a bouncy seat or a swing that clicks in so we can make dinner, and soon after to sleep in a crib. We in the west have diverged from tradition and have gotten to the point so that objects are defining our baby’s existence more so than our bodies.

“To remove the newborn baby from his mother and place it on its back or on its front on a flat surface, often uncovered is to fail to understand the newborn’s great need for enfoldment, to be supported rocked and covered from all sides, and that the infant may only gradually be introduced to the world of more open spaces. From the supporting, continuous, tangible presence of his mother the infant will gradually come to move some distance toward the outside world”. (Montagu, 294)

The Fetal Tuck

Newborns are virtually impossible to stretch out unless wrapped or swaddled. When you place an infant flat on his back, his thighs will usually be pulled up towards his chest (Schon, 2007), or when sleeping straddled and bent in a frog position. “The fetal tuck, the natural position of babies is the most calming and the most adaptive. Infants use less oxygen which conserves energy and waste less calories and they digest their food better. It is also the best position for thermoregulation because of reduced stomach exposure. We have more efficient temperature regulating cells and more fat on the back side of our bodies as well. When we hold our infants stomach to stomach we are protecting all the receptor and vital organs (Montagu, 1986). The instinctual flexed widespread legs that an infant maintains when picked up, coupled with the palmar plantar reflex that helps an infant to cling to his mother, suggests that infants little bodies are adapted to be carried upright and oriented toward their mothers.

Flexed Abducted (Seated Straddling) Position Supports Legs

Upright baby carriers that support the legs carry a baby as a mother would naturally would in arms do not compromise a baby’s spine or hips (Kirkilionis, 2002). When an infants legs are flexed and straddled, the instinctive position that his little body assumes when picked up, the head of his femur (bone of the thigh) fills out the hip socket (acetabulum). The hip socket is filled most evenly when the legs are pulled up to roughly 100 degrees and spread roughly 40 degrees at the same time (Kirkilionis, 2002). DDH does not occur when an infant’s legs are supported.  Actually this is the position that many doctors  Interestingly enough the Netsilik Eskimos who are big babywearers don’t use papooses but carry their infants in their amautis of their parkas. They assume a seated straddling position on their mother’s back inside their coats (Montagu, 1986). There have been no studies indicating prevalence of either DDH or spondylolisthesis in this northern Eskimo baby carrying group. Their hips and spines develop normally. If we look at the great scheme of things man and his hominid ancestors have always carried their babies upright on their fronts, hips, or backs.

This baby’s spine, hips, and legs are supported.

A mother using either her arms or a simple piece of cloth, supported her baby’s legs in a flexed (with the knees bent) abducted (away from midline) position supporting the hip and the spine. There are many ergonomic baby carriers out there that support babies legs in this flexed abducted position, aiding us in carrying our babies how our arms would. Instead of fabric at the crotch which contributes no leg support, or swaddling the legs which is too restrictive, ergonomic carriers put the baby in the position that supports the legs just as a mothers arms would.  The flexed abducted position is what infants are hard-wired to assume when picked up. (Schon, 2007). It is what nature intended- legs spread around the mother’s hip, back or torso with knees bent in a seated position.

A mother’s arms supports the baby’s bottom and legs. Subsequently, pressure is taken off the spine and the weight of the baby is evenly distributed in an ergonomic position.

The fabric is pulled to the back of the baby’s knees offering proper leg support. The legs should be pulled to form at least a 90 degree angle. 100 degrees is optimal for proper hip development.

Photo on right shows proper spine position, oriented toward mother, proper leg support, proper head/neck support

Autonomic System Regulation Easier for Carried Infants

The mother/infant relationship actually provides physiological regulation of the infant’s autonomic system. Studies have shown that when an infant is taken away from his mother he experiences a “decreased heart rate, temperature decreases, sleep disturbances and EEG changes”- representing an impairment in the regulating processes of his own little body (Archer, 1992)). On separating mother and baby, his immune system weakens. His body literally stops producing as many leukocytes. But when mother rejoins him, he strengthens again (Montagu,1986). An infant’s body physically needs his mother present to help regulate his own body.

Other than this, being upright on mother’s chest also :

  • stimulate all their senses
  • feel secure
  • tunes vestibular system
  • prevent ear infection and relieves symptoms of GERD (Gastroesophageal reflux disease)
  • improve respiratory system

These are the reasons that I decided to go and get a sling. Not yet tried on it cos she has been quite cranky today due to over-tiredness I suppose. She always cry and gets cranky if she gets disturbed from her sleep or not enough sleep. Sigh~

Now I think it’s time I should get back to my fx, So far this month has been not bad. :) At least boost up my morale. Jiayou….


  1. it’s like the storie of the life of my daughter!

    hello from France, Paul

  2. Hi
    I found your article very useful.Decided aganst buying a bb carrier.
    Thanksyou so much fo sharing it.
    Warm Regards

  3. Decided against using the one I bought.Thanx a lot.

    • glad tat u found it useful. I have bought one baby carrier before I knew about this. And me too, decided against using it. Instead, I m using a sling for my baby. =)

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