The Importance of Crawling for an Infant

By Dr Cynthia Horner

All parents want their infants and children to progress as quickly as possible in their motor and intellectual development.  Although each child has their own developmental timetable there are some stages of neurological development that are important such as crawling and the disappearance of what is termed primitive reflexes  Each stage of movement molds the nervous system in a different way. Pushing a child to progress too quickly may cause them to skip a stage or not fully benefit from a stage of  development.

 

Crawling

But how important is crawling before walking? Infants kick and move their arms in opposite directions while lying on their backs, then advance these same movements face down to crawling. Cross body movements such as crawling have several positive and important effects on a baby’s neurological development. As a baby crawls and moves opposite arms and legs he is creating connections between the two hemispheres in his brain, initiating these two areas to communicate and exchange information. Crawling also helps to develop a healthy spine as the limbs are asked to rotate around the axis of the spine creating torsion in the spinal joints that prepares them for standing upright. As a baby crawls he must work against gravity to balance his body as he shifts his weight. This complex skill develops the cerebellum at the back of the brain. The pressure on limbs while moving strengthens joints.

Placing a child in a devise that puts him in the upright position allowing his legs to move independent of his arms may be easier on the parent but robs him of the rich experiences of the sensation of different textures and pressures on his hands and knees and in balancing his body through trial and error. Sitting or standing upright in a walker before crawling creates development of the lower extremities out of sync with the upper extremities and cross movements are not needed. Encouraging babies to crawl means plenty of belly time and attention from the care giver as crawling means moving and exploring the world.

One way I check my infant patients to determine if their brain is  maturing as it should is to check their primitive reflexes.

Primitive Reflexes

When I speak of primitive reflexes I am speaking of reflexes that all healthy humans have as an infant but should go away as our nervous system matures. They are called primitive because they originate in the lower brain, the brainstem. These reflexes are present when we are infants and children to help us survive. As infants develop the strength, control and coordination to balance themselves in gravity; postural reflexes take over and primitive reflexes are inhibited. If these reflexes are not fully developed in infancy, control and coordination of movement can be affected. This is known as Neuro Developmental Delay or NDD.

On the other hand if postural reflexes do not develop and primitive reflexes remain present the child will experience difficulty at a later time with;

• balance
• sleeping
• immune function
• impulse control
• fine motor skills
• motor development of eyes
• eye hand coordination

if the reason for these difficulties is not found and corrected it can lead to frustration, hyperactivity, stress, difficulty concentrating as well as emotional and learning problems.

 

Some primitive reflexes I test for in an infant or child examination;

Rooting Reflex – Infants will turn their head and suck my gloved finger when I brush their cheek.

It should be present from birth to 4 months of age when voluntary sucking takes over

 

Galant Reflex – When the skin alongside the spine if softly strokedupward the  baby’s muscles will contract causing extension of their back or their shoulder to be pulled slightly toward their hip. This reflex is thought to help with movement of the spine and with the neurological wiring necessary with emptying the bladder.

This should be inhibited between 3 and 9 months old.

 

Asymmetrical Tonic Neck Reflex (ATNR)– This reflex is activated as a result of turning the infant’s head to one side its arm and leg on the same side extends while the opposite arm and leg flex or bend, sometimes overhead. (neck muscles will have some effect on arm movement up to 1 year old). This reflex is a precursor to the hand/eye coordination of the infant. It also prepares the infant for voluntary reaching.

This reflex should be inhibited by time the infants is 6 months old.

                                    

Symmetrical Tonic Neck Reflex  (STNR) – This reflex is the precursor to crawling. I test this by having the baby sit back on all fours and look up. This reflex allows the baby to straighten his arms and bend its legs when it looks up. The STNR reflex is present in normal development for a relatively short time span and is normally lost at 11 months after birth. If it is not lost, it can affect a child’s ability to crawl on hands and knees. Crawling is a major developmental milestone, as a baby crawls, as well as looking ahead; babies also learn hand-eye coordination from the movement of the hands.

It should be present from about 8 to 11 months.

 

Tonic Labyrinthine Reflex (TLR)

The TLR is the opposite of STNR; it occurs before STNR, when a baby placed on their back and their head is tilted backwards TLR causes the baby to straighten its legs, and point its toes, while making fists with its hands likewise when the head goes down the limbs fold in. It is active during the birthing process. It is linked to balance and muscle tone. If this reflex persists it will disrupt balance and gross motor skills.

This reflex should be fully present from the time of birth to 4 months old.

 

Morro Reflex (or startle reflex) – Sudden head movements will cause a rapid extension of the infant’s limbs and a large inhalation or breath followed by a pulling in of the limbs and crying. It is initiated by holding the infant on their back then quickly lowering my arms about a foot. It is a protective mechanism.

It should be gone by 3 months.

 

Landau Reflex – This is an instinctive reaction in babies from about three months of age to one year, wherein an infant, held in a face down position, will lift their head and fully extend their legs. It is useful to keep a baby from smothering when laid face-down. It disappears once the child has enough muscle control to no longer need it. Without Landau’s reflex, a baby placed on a baby blanket would only be able to turn their head side to side, meaning that same baby blanket would occupy most of their field of vision and leave them unaware of things happening above their level.

It should be gone at about 1 year of age.

 

The Palmar Grasp Reflex – This reflex appears at birth and persists until five or six months of age. When an object is placed in the infant’s hand and strokes their palm, the fingers will close and they will grasp it. The grip is strong but unpredictable; though it may be able to support the child’s weight, they may also release their grip suddenly and without warning. The reverse motion can be induced by stroking the back or side of the hand, the hand will open.

It should be gone around 5 to 6 months of age.

 

Plantar (or foot) Reflex – A plantar reflex is a normal reflex that involves flexion of the foot, which moves toes away from the shin and curls them down. In an abnormal plantar reflex (aka Babinski Sign) the foot angles towards the shin (big toe curls up). Big toe curling up is a normal response in babies under about 1 year. When babies need to step on the floor to walk the toes should turn downward to ‘grip’ the ground. I elicit this reflex by gently stroking the bottom of the foot with the handle of my reflex hammer.

Expect it to be gone 8 to 10 months of age.

What I have learned from my patients: “Learning something new is inspiring.”