What is the midline?
If you imagine your body folded in half vertically, the crease down the middle would be the midline. It is the imaginary centreline dividing the left and right sides of the body.
When one arm or leg reaches over to the opposite side of the body, this is crossing the midline. For example, using your left hand to touch your right foot.
Why is crossing the midline important?
The ability to cross the midline of the body is significant for both cognitive and physical development as it indicates that both sides of the brain are working together. It is also an indicator of developmental skills such as bilateral coordination and core strength. A child’s ability to cross the midline will impact their ability to read and write, as well as other motor skills.
Developmentally, children begin crossing the midline around 7 months through movements such as passing toys from one hand to another and progresses to crawling.
As children grow and their ability to cross the midline develops, they will begin to display dominance in one hand. However, if they avoid crossing the midline, both hands will be equally involved in activities, i.e. using left hand for tasks on the left side, right hand for tasks on the right side. This may make them appear ambidextrous but could actually be a sign of developmental issues.
Other signs are:
- Difficulty with visual tracking (a skill required for reading)
- Swapping hands when drawing or writing across a page
- Difficulties with gross motor skills, such as crawling, skipping, climbing
- Kicking a ball with the foot closest rather than having a dominant foot
- Difficulties with age appropriate self-care tasks
If your child has difficulties crossing the midline, your health professional can do an assessment and may refer you to an Occupational Therapist for help.
Activities to do at home
It is easy to help your child strengthen their ability to cross the midline with simple activities such as:
- Sorting games. Get your child to sort objects with one hand into a container on the opposite side (no hand swapping allowed!)
- Marching or dancing to music using both arms and legs. Flossing is actually great for crossing the midline!
- Using ribbons or streamers do figure 8’s in the air.
- Any sports such as soccer, cricket, baseball, tennis or even just catch.
- Household tasks such as wiping benches, sweeping, vacuuming.
There are some more great ideas here.