What exactly is crossing the midline? I’ve learned a lot about this from my Occupational Therapy colleagues. Think of the midline as an imaginary line that runs down the middle part of the body that divides the body into the right and left sides. Crossing the midline means that a child is able to reach across the middle of their body with their arms and/or legs and perform a task on the opposite side of their body. This skill usually becomes established around 3-4 years old. There are several everyday activities that you can do to work on crossing the midline.
Read more here, and you can see the video here: