The Midline Mystery :: What Our Preschool Teacher Taught Us About an Imaginary Line


Last school year my son started pre-k. And boy was I super excited that he was going to learn new things everyday. Little did I know, I would be the one learning something new.

As a mother, you see your children differently than others. To me, my children are the most beautiful, the smartest, and most unique children God has blessed the world with. However, sometimes our “mom” eyes can hide truths we’d rather not see.

And that’s exactly what mine were doing. I knew my son did things a little differently than other children. And I always thought it was because he was still carrying some of his adorable baby weight (which I miss so much now that he looks so grown up at five years old.)

midline, brain, Albuquerque Moms BlogThe first sign was the way he walked down the stairs. He had to go down one foot at a time to the same step and repeat. Again, I thought it was a normal four-year-old thing to do. The second was the way he held a pencil. He constantly switched hands. Again, I thought he was just trying to figure out which one was the dominant hand. So time went on and along came our very first parent-teacher conference. I was so excited to hear all about his accomplishments and we did. The teacher told us about how kind he was with other kids, how he enjoyed playing independently, and how he loved making science projects. But then she said it.

“Also, Z is not ‘crossing his midline,’ and he is going to need to do special activities to help him.” 

I was left speechless. My main thought was “What is this ‘midline’ she is talking about, and how did I miss this?”

So what is “crossing the midline”?

A midline is a reference to an imaginary line that divides our bodies down the middle and crossing that line refers to someone’s ability to reach over that line with an arm or leg and perform a task on the opposite side of their body. For example, using your right hand to touch your left knee.

After doing some research, I learned that “crossing the midline” is important in child development.

It means the left and right hemispheres of the brain are properly communicating. Communication between the two is an essential role in learning, reading, coordination, etc.  The more these two sides communicate, the stronger the connection becomes and the easier it becomes for the developing brain to process and perform.

Some signs that a child may have trouble crossing the midline:

  • Trouble holding a pencil
  • Poor penmanship
  • Using left hand for activities on the left side and right for right side activities
  • Trouble with upper/lower body coordination (riding a bike, jumping jacks)
  • Tracking words while reading from left to right.

My son does have most of these signs. But I always thought he would outgrow them. Now I know he just needs some extra help and we’ve been on our way ever since!


Here are some activities we try to incorporate in our week.

  • Figure 8s: Draw a large figure 8 on a chalkboard/sidewalk/paper and ask him/her to trace the figure with their finger using their dominant hand. The shape of the 8 will force them to cross the mid-line!
  • Practice: Practice with zippers, buttons, and shoelaces.
  • Twister: This classic game is probably one of the best exercises! It’s super fun and will not seem like an “exercise” to your child. They will be crossing the mid-line and not even knowing it!
  • Simon Says: While being “Simon” you can ask your child to do different gross motor movements. For example, “Simon says reach your right hand over and touch your left shoulder.”
  • Yoga: Stretching and concentrating on the poses will help with coordination, balance, and patience.
  • Arts & Crafts: Coloring, drawing, threading, cutting, pasting and folding.

Originally published September 2019.

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