What is ‘midline’ and why is ‘crossing the midline’ important for your child’s brain development?​

The term “crossing the midline” is often said during Occupational Therapy sessions. It is described as an important movement activity but not often explained. This leaves many parents thinking… ‘What is crossing the midline? Why is it so important?’

By Annaliz Blackmore, Occupational Therapist.

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What is midline?

Imagine a line that starts from the top of your head and draws straight down to the point between your two feet. This figurative line splits your body into left and right halves and is known as the midline. The term ‘crossing the midline’ depicts the movement of a body part over the midline from one side to the other side of the body to complete a task.

Why is it important?

Neurologically, lack of midline crossing could result in poor communication between the left and right sides (hemispheres) of the brain. The left and right side both like to work in isolation and crossing the midline requires communicate between both sides (corpus callosum involvement). Activities that require you to cross the midline therefore fully engages your brain (cerebral cortex) which can cause mental fatigue. It is recommended that you child regularly completes activities that cross the midline to assist in both hemispheres communicating well to facilitate and strengthen the neural networks to coordinate movement and learning.

Physiologically, crossing the midline can assist strengthening the dominant hand’s ability to complete fine motor skills. The dominant hand needs to reach over the body to complete most fine motor tasks. Up-skilling the dominants hand ability to reach over can increase its strength and coordination required for fine motor tasks. If both hands are being used equality than the development of a dominant hand can be delayed and consequently delay fine motor skills. Furthermore, as you child gets better at reach over and understanding where their body is in space, their coordination and confidence improves. Crossing the midline also requires an adequate level of core support and strength to allow your child reach over to their other side (trunk rotation) when completing a task.

What is ‘midline’ and why is ‘crossing the midline’ important for your child’s brain development?​

Why is crossing the midline important in Occupational Therapy?

Occupational Therapy assists in the activities that children need, desire and are expected to do. This includes but is not limited to dressing, feeding, toileting, writing, and play. These can be generalised in the term, ‘activities of daily living’. Adequate fine motor skills are essential for all activities of daily living. Therefore, Occupational Therapist often up-skill children’s fine motor skills so that they can engage in their activities of daily living. Activities that provide opportunities for children to cross the midline reinforce the pathways between the hemispheres and allows for the fundamentals of fine motor skills, such as the development of their dominant hand, as well as enhancing a child’s coordination and learning (ie. reading – the ability to track letters along the line of a page).

Crossing the midline activities also develops a child’s gross motor skills such as coordination and balance. Gross motor development is also essential in order to maintain a children’s development with their peers. A child’s poor gross motor skills can also negatively impact their attention and working memory. The child can be too preoccupied coordinating themselves that they are not retaining the information they need in their working memory. Attention and working memory are necessary for completing the more complex activities of daily living such as dressing or writing (e.g. knowing the sequences of dressing themselves or having enough attention to complete a writing task). Therefore, therapists incorporate crossing the midline activities to address numerous avenues of up-skilling and learning for the children.

What is ‘midline’ and why is ‘crossing the midline’ important for your child’s brain development?​

How to cross the midline?

1. First start with bilateral coordination activities. Move both sides of the body symmetrically such as pushing or pulling objects. For example, completing “head and shoulders, knees and toes” with both hands.
2.When they have mastered bilateral coordination, begin crossing the midline. For example, have them mirror your movements. Stand in front of them, ask them to copy you and have your hand touch the opposite shoulder, then have your hands touch the opposite hip, etc.
3. While marching are they able to tap their opposite knee. ie. their right hand on left knee and then opposite.. and then march backwards and complete, or complete with eyes closed?
4. As coordination progresses, introduce activities that require a strong hand and assistive hand. For example, using scissors with a dominant hand and having the assistive hand move the paper.

What is ‘midline’ and why is ‘crossing the midline’ important for your child’s brain development?​

Activities for home:

Reaching to the opposite side
Asking the child to reach to the opposite side through passing materials, ie. pen, spoon, clothes, food from the opposite side or setting up activities on their non preferred side.

Reaching for Balls
Have your child sitting or standing in front of abasket and have them place the balls inside the basket. Then, place balls on the left side of the child and place the basket on their right -have them reach for the ball with their right hand and place it in the basket. Make it fun by asking them to put all the balls in the basket as fast as they can. Have them beat the time for their personal best. Swap the sides of the basket and balls then repeat. Make sure they reach over and use their opposite hand.
Have them stand ready to catch a ball that is thrown or rolled and to them off centre for them to catch.
Equipment: balls and basket

Numbered cards
Have different cards blue tacked to the wall within your child’s field of vision and reach. Tell the child to reach for the card you say and ask them to switch hands between each card (i.e. “reach for the 4”, “reach for the 2”, etc). Try and purposefully choose cards that make the children subconsciously cross their midline.
Equipment: cards and blue tac

Make a maze/ complete the lazy 8
Flatten a piece of cardboard and draw mazes that go from the left side of the cardboard to the right. Have the child sit in front of the cardboard and ask them to trace their way from one side of the maze with the other. Keep it interesting by pretending their stuffed animal is going through the maze or a toy car.
Equipment: Cardboard, pen, ruler, car or toy


  • Poor core control will affect their truck rotation therefore their ability to reach over the midline
  • Allow for self-correction during an activity, if they continue to incorrectly complete an activity allow for verbal cues then physical cues
  • A child will cross the midline with the dominant hand more often than their other hand

"Alone we can do so little; together we can do so much"

– Helen Keller

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