If you’ve spent any time in the pediatric rehabilitation world, you’ve probably heard the phrase “crossing midline”. But what does that mean? And why are occupational therapists, physical therapists and speech/language pathologists so excited about seeing this skill? Why is a simple-sounding thing like crossing midline necessary for brushing your teeth, getting dressed, handwriting and reading?

What Is Midline?
Midline is an imaginary center line on the body. Crossing midline, therefore, can mean a right foot or arm crossing to the left side of the body or a left hand/leg reaching to the right side of the body for a task. Another way to look at it: the two sides of the body are acting independently of each other, instead of the right being a mirror image of the left.

What does “crossing midline” do for your brain?
This simple sounding activity creates some pretty complex results, like developing and strengthening pathways in the brain that connect the two hemispheres of the brain. This stronger connection means increased activity in the brain for a healthier and more efficient brain, increased cognition and a factor that helps enable coordination. This coordination can be used in either gross motor activities like riding a bicycle and crawling or in fine motor activities like unscrewing the cap on a peanut butter jar and playing an instrument.

What does not “crossing midline” feel like?

-Try putting your left sock on with only your left hand
-What about putting on a jacket?
-Try throwing a ball without any follow-through
-Imagine how you would steer a car without both right and left hands?

What if you don’t “cross midline”?
Children that don’t practice crossing midline might experience difficulty with any tasks that require different motions from the right and left sides. These difficulties might look like no dominant hand/foot and therefore decreased ability to use these body parts for skilled activities like playing soccer, handwriting, smooth walking/running patterns and drawing/coloring/using scissors. Difficulty crossing midline may be demonstrated more frequently in children with developmental delays (Surberg & Eason, 1999) or learning disabilities (Woodard & Surberg, 1999). Crossing midline develops the communication connections needed for your body to accomplish the goal-directed and coordinated tasks essential to your day as well as providing the cognitive exercise that develops awareness of the body, its parts and functions.

What can you do & when can you start?
-You can start crossing midline when Baby starts looking at and reaching for toys. Just position the toy on one side and encourage the opposite side hand to reach for it by gently tapping that hand or gently holding the same-side hand. Make sure Baby experiences success in reaching with the opposite-side hand.

-Toddlers / Any age: Crawling is so important for proper development for many reasons, including the fact that that it makes opposite sides of the body act independently in a coordinated fashion via crossing midline: right hand with left knee and then left hand with right knee. Don’t skip crawling! Getting dressed can be a great crossing midline activity especially with button-up shirts, socks and shoes.

-School Age: Arts and crafts projects not only build good memories, they build better brain connections, especially when one hand does the writing, hammering or holds the scissors, while the other hand steadies the paper, holds the nail or moves paper to help cut out shapes. Not crafty? Play catch, soccer, basketball or make up your own game that involves throwing or kicking!

-High school / Adult: Be aware of how often you cross midline yourself. Research shows that people use their dominant hands for most tasks, regardless of which side of the body the task is on. This is an important function of crossing midline: that a preferred/dominant/more skilled hand is developed. However, your brain functions by the “use it or lose it” maxim, so go ahead and try reaching across with your non-dominant hand, so that it maintains a certain level of skill.


Surburg, P. R. (1999). Midline-crossing inhibition: An indicator of developmental delay. Laterality: Asymmetries of Body, Brain and Cognition, 4(4), 333-343.

Woodard, R. J. & Surburg, P. R. (1999). Midline crossing behavior in children with learning disabilities. Adapted physical Activity Quarterly 16, 155-166