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Postural ontogenesis

Postural ontogenesis: What do you need to know about your baby!

Saul Yudelowitz BSc (Hons)

Postural ontogenesis is automatically triggered by optical orientation and tactile stimulus. It consists of various movement patterns and this is where humans learns their movement patterns. The following two motor functions are the main foundation movement patterns:

  1. Stabilization of the spine in the sagital plane needs to occur first. It is linked to optical orientation and is accomplished by the end of the fourth month. It is the result of the muscular co-activation required for erect posture.

  1. The postural prone patterns are identical but differ by the points of support. Phasic movement only develops after stabilization in the sagital plane has occurred. This can be seen as stepping forward and grasping and the supports function, all of these are related to trunk rotation.

Stepping forward and support functions develop according to two patterns.

  1. Stepping forward and grasping take place on the ipsilateral side as does support by lower and upper extremity occur on the ipsilateral side.

  1. Stepping forward and support functions are on contralateral sides.

At first the homolateral pattern of supine grasping develops. So stepping forward and support take place at ipsilateral sides and then grasping can occur on contralateral side.
What this basically means is, initially grasping takes place from the side, then in the central plane at about four and a half months and then grasping induces trunk rotation due to contralateral grasping by six months. All this occurs while the baby is in the supine position. The induction of trunk rotation by contralateral grasping is the stimulus to move from supine to prone.

Stepping forward and grasping on contralateral sides is seen in the prone infant in six and a half months. Then it is seen when crawling on all fours and then standing up.

Through treatment, a motor reflex response to sagital plane stabilization can be evoked, followed by the ipsilateral stepping forward and support and then the contralateral stepping forward and support. This is how the body has learnt to create movement.

Head rotation should occur in the same direction as the stepping forward limb. Once again what this means is, if you look at a human when they walk, the left lower limb swings forward while at the same time the right upper limb swings forward. This movement is coupled with trunk rotation to the left.

Once baby has moved into the prone position, they will begin to lift up and try support the weight of their head. The human head is about 7 and a half percent of total body weight, so this is a significant weight. Once baby can lift and hold their head up, the lordosis of the cervical spine is formed.
Optical orientation and tactile stimulus continue do drive the movement patterns as baby can now see more of the world. Babies will try to satisfy their needs by moving towards objects. Hunger is one such driver and babies will move to look for food.

Initially movement occurs by support on the ipsilateral lower and upper extremities. So baby will support the body weight on the right arm and right leg while trying to reach with the left arm. If parents observe this phase closely they shall see their baby wiggle their pelvis to begin the rotation that allows for contralateral, reciprocal support and movement.

This is a very important phase of development and should not be rushed as it is required to co-ordinate the inner and outer muscular units for power development in the future. Untimely baby will reach the point where the following occurs in a smooth co-ordinated fashion:

  1. The head will rotate to the left while
  2. The left lower limb will move upward towards the shoulder and
  3. The right upper limb will move upward away from the shoulder, this occurs while the
  4. Right lower limb pushes away from the hip to assist in movement and the
  5. Left upper limb is pulled downwards away from the left shoulder to assist in movement.

This is the reptilian phase of movement. If you look at all human movement it is based on this pattern, just as walking was described above!

Baby will soon begin to get their belly off the floor and this will allow for a reduced rotation of head movement and a move visual orientation with a change in the tactile stimulated areas. It is prudent not to rush your baby through this reptilian phase of movement into sitting and walking, they will get their on their own. Do not worry about what is said in terms of when baby should be walking unless the time difference is significant.

Having rehabilitated some of the worlds top Olympic athletes, exercise enthusiasts, patients with poor posture and the disabled, it always amazes them when I assess how they move in the reptilian phase! If you want to give your baby an excellent head start at avoiding many of the common musculoskeletal complaints that 80% of the general population present with later in life, let nature do what it was designed to do and remember:

Most of all as a parent you should enjoy watching your child develop as this is an excellent way to learnt how to understand their needs! Since we are human we all have the same needs that are a little different between everyone.

This article has been written for a medical journal, should you not know the meaning of the medical words, do look them up or just email us. It is important to understand how posture develops.

If you have any questions on how your babyís posture develops or would like your child assessed, email us for an appointment.

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