Psychomotor development of the child - 3 to 4 months


In the previous article from this serie we talked about how can we check our baby at home to check its correct psychomotor development after birth up to the second month of the age, and how to evaluate and test the reflexes of the child. Now we will focus more in detail on the 3rd and 4th month of baby’s life.


What should the baby be able to do while laying on the back?

The child should be able to how its body in a straight axis.

Head, trunk and legs are in one straight line. The baby holds the head more down, the shoulders are tilted and the belly is turned to the side, where the baby turns the head. The child should be able in the 3rd month of life, to keep symmetrical posture and keep the head, neck, trunk and legs in one straight line, meanwhile the axis of the pelvis and shoulders is in right angle to the longitudinal axis.

Another key point typical for reaching 3 months of life is that the child is able to lift the legs into 90 degrees in all joints of the legs.

That means that the child is able to lift up the legs along with the symmetrical posture of the body, the thighs are in a right angle to the mat, the lower legs are horizontally with the mat and the feets are again in a right angle to the mat.

3 months old baby laying on the back should normally play with its own hands.

The child is consciously playing with its own hands, observes them, puts them in the mouth. From this moment on, everything the baby will come in contact with its hands, it will also want to taste it. To test the quality of the object with its tongue, similarly as the child does it with hands. The hands should be for most of the time open. If the child is able to reach the toy or your finger, it will first try to touch the object first from the pinky finger side and then it will cover with its whole hand. The thumb is still working on the side of other fingers (later it will be adjusted as it is typical by people).

What should the baby be able to do while laying on the stomach?


The child should be able to rest on both elbows and forearms.

The head and neck are stretched in the axis of the trunk. The trunk is slightly above the ground, and the baby is resting against the ground with its belly button. Most of the body and head is therefore supported against the gravitational force.

When do we evaluate it: it is best to evaluate the child when it is naked.

How do we evaluate: you can again evaluate the quality of the straight posture. The body is supported above the ground, because the child is activating simultaneously muscles on the front and back side of the trunk and nape. If the baby straightens up only by using the muscles on the back side of the trunk and nape, you will see wrinkles across the back, beneath the shoulder blades an in waist. The neck will be short, as if it dropped between the shoulders of the child.

Goal of observing: If the child is able to correctly straighten the trunk and head, you wont see any wrinkles on the back or neck.

What if the child won’t be able to do certain movements?

Your child should be able to achieve the above mentioned abilities. If the child is not able to use certain key movement programs, their absence will be manifested in following months. Characteristic, well observed example can be incorrect body posture from the time, since the child stands and walks, and further even in the preschool and school age.

Because if the child cannot tilt the pelvis enough by the 3 month of life, and activate abdominal muscle and deep muscles of the spine, these insufficiencies could manifest in later age in incorrect body posture, head being pushed too much forward, shoulder blades being too far from the chest - reminding wings, bulging belly, walking with toes being turned inwardly etc…

Similarly, if the child in this age is not able to keep a symmetrical position at least for short moment, it will be manifested later as an incorrect body posture and it can later develop into scoliosis of the spine.



What to do if we find out some discrepancy?
Given the fact that controlling the movements is clearly in competence of CNS activity (central nervous system), if you observe some problems, we recommend to get advice about possible exercising based on the activation of the movement patterns in the CNS with pediatrician, neurologist or directly with a physiotherapist.




What should the baby be able to do while laying on the back?

While laying on the back, the child tries to reach the toy.

If you hand the toy to the child from the right side, the child will try to reach it with the right hand and vice versa. If you hand the toy to the child from right side and you will slowly move to the left, the child will observe the toy, the child will try to reach it with right hand and then after crossing middle line it will try to reach it with left hand. After reach age 5 months, the child will be able to reach for the toy even after crossing the middle line with right hand. This new ability will enable the child to rotate to the side and then on the belly.


Similarly as other movements, grasping is depending on the stability of the child’s position. Therefore if the child didn’t reach the symmetrical position by the 3 month, the development of grasping and relieving the fingers and hands will be slowed down.

When the child lies down, it is able to lift the legs even higher, and touch the hips that way, or alternatively reach on its thighs.


What should the baby do while lying on the back?

Child’s interest in the toy gets stronger, which leads the child to further development.

While the child lying on the back, offer the toy in the middle line, which is directly above face, the child won’t be able to decide which hand will it use for grasping the toy. This will manifest by „motor unrest”, when the child will be able to shake with its hands, kick with the legs, alternatively bend backwards, opening mouth, as if the child would try to grasp the toy with its whole body.

Examining the childs development

In this time period the child will be trying to rotate to the side.

If the child has strong enough abdominal muscles and its coordination of the front and back side of the trunk will be good, the child will be able to rotate to the side to grasp the toy.

Correct coordination and rotation is when the child is able to pull the legs as close as possible towards the trunk, lifting the bottom from the ground and then rotating after the toy. Ideally if the toy will be placed right next to the child on the ground. Good indication for you, when the baby is will start to rotate soon, is when it able to place the arm in 90 degree to the body.

What should the baby be able to do while laying on the stomach?

Laying on the stomach in this month leads to a big advance. The baby is able to lean against one arm, against the elbow or forearm, and trying to reach objects with the second arm. At the same time, the child has to support itself by a bending and resting on one knee.

One of the main measures is, whether 5 months old child is able to lift its arm above the horizontal line. At this moment it is clear that the development will advance, and after a while the child will be able to stand up and walk. This is one of the indicators, which is evaluated by children with cerebral palsy while evaluating the prognosis of the development of the child.

Another part:


Published in magazine Uzlíček, no: 4/2007
Author: Mgr. Iva Bílková, FYZIOklinika fyzioterapie Ltd, Prague, Czech Republic

Login to post comments

Exercises that might interest you

Videos that might interest you

What might interest you

Why is swimming good for children?

My own daughter inspired me to write this article. As a mother i want to give my daughter all the…

Psychomotor development of the child - 13 to 18 months

Your child made in the last year a big advance, which is mostly visible in the physical abilities. It learned…

Psychomotor development of the child - 7 to 8 months

In the previous part of this serie we described according to which basic signals you can evaluated the development of…