The midline is an imaginary line that runs down the body, separating it in half vertically from head to toe thus dividing the body into right and left halves. "Crossing the midline" refers to the ability to move a part of the body-- such as a hand, foot or eye-- into the space of the other hand, foot or eye. Being able to cross the midline indicates that the child has reached the point in his or her development that the right and left side of the brain are working in tandem. An example of crossing the midline is using your right hand to reach over your body and scratch your left elbow.Connecting the two sides of the brain is a fiber bridge known as the corpus callosum. When children do cross-lateral movements (arm and leg movements that cross over from one side of the body to the other) the two sides of the brain are forced to communicate and this strengthens the nerve-cell pathways that link both sides of the brain through the corpus callosum.
Crossing the midline is necessary for reading and writing because in order to read and write one must work from one side of the paper to the other fluidly.
To encourage cross-lateral movement:
- Sing songs and repeat chants using hand motions that cross the midline of the body such as “Pat-a-Cake” and “Hot Cross Buns.”
- Dance using streamer ribbons or scarves. Play a music CD and ask children follow along as you swish the ribbon or scarf across the front of your body, make figure eights in the air, circle the streamer in front of your body like a Ferris wheel or circle it over your head like a helicopter blade.
- Play games like Simon Says or Follow the Leader where actions require crossing the midline, such as touching your right knee with your left hand.
In my next post, we’ll look at more playful ways to encourage brain development. Stay tuned!
