Why Crossing the Midline Matters

Categories: Resources

If you spend a lot of time with occupational therapists, you probably have heard them reference crossing the midline.  We like to talk about this topic a lot especially when working with young kids.  Today, let’s explore what crossing the midline actually means, why it is important, and how you can encourage development of this skill.

What is the midline?

The midline is an imaginary vertical line that goes from the head to the feet which separates the right and left sides of the body.

What does it mean to cross the midline?

This sounds like a weird term but it actually is very simple.  Crossing the midline refers to when a child can easily and spontaneously use a body part on the other side of the body.  When a child easily crosses midline, he can use his dominant right hand to reach across to grab an item on the left side of his body without having to stop and switch hands in the middle.  He can fluidly throw a ball by stepping forward with the left foot and throwing with the right hand. He can easily start at the left margin of the paper and write across the paper horizontally.  

Why is crossing the midline important?

Crossing midline is an incredibly important skill for a lot of reasons. This skill starts to develop in infancy. Babies are first able to touch objects placed in front of their shoulder, then right at the midline, and then across it. I haven’t found any specific information as to when exactly this skill should be in place, but my own opinion is that we look for kids to cross midline as they enter preschool. Being able to cross midline is an essential part of developing bilateral coordination, or the ability to use two hands together.  Bilateral coordination is required for many important skills, such as handwriting, cutting, coloring, dressing, buttoning. Crossing midline can help develop hand dominance, which is super important as kids enter school.  Additionally, when kids cross midline, both sides of the brain communicate with each other which is very helpful.

Therefore, if a child has difficulty crossing midline, he will have a lot of trouble effectively completing many important tasks at school and at home.  This is why crossing midline matters.


What are some red flags to look for?

There are some red flags to watch for that would indicate that a child is having difficulty crossing midline. 

  • may look clumsy during activities that require use of two hands
  • may shift his entire body over during tabletop tasks to avoid crossing midline
  • may tilt the paper when writing to avoid crossing over midline
  • may not have a dominant hand, switches hands often
  • difficulty scanning left to right when reading and tracking objects visually

It can be tricky at times to notice if a child is or is not crossing midline.  Kids may shift their whole body as a unit and actually avoid crossing midline even if it looks like initially they may be. Ideally, when looking at having a child cross over midline with upper extremities, the pelvis and lower body remain in a stable position which allows the trunk and upper body to rotate and facilitate crossing midline.  If the lower body and pelvis rotate too, midline crossing doesn’t happen.  

Activities to encourage crossing midline

There are a lot of fun and easy ways to incorporate midline crossing activities into your day!

Gross Motor Activities

  • Crawling and climbing on playground equipment.
  • Throwing and catching a ball or bean bag, sitting back to back and passing a ball to each other.
  • Exercises – cross crawls, windmills, sidebends.  Check out Brain Gym! YouTube has a lot of resources too.

Art and fine motor activities

  • Painting at an easel
  • Drawing a figure 8
  • Drawing rainbows
  • Wiping the desks

Strategic placement of materials during activities

  • enter any play scheme where a child needs to reach for and manipulate materials and you can embed midline crossing into it.
  • Think about blocks and puzzles. Try placing pieces on the non dominant side and encouraging the child to reach for them before putting the pieces together.

Have more questions?

Be sure to contact your OT for further evaluation if you are still concerned or need specific recommendations or guidance. Check out the resources below for more information and ideas for embedding midline crossing activities into your day.

References and Resources

Katie McKenna, MS, OTR/L
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