Ask an OT: What is ‘Crossing the Midline’?

July 7, 2021
Ask an OT: What is ‘Crossing the Midline’?

Our body has an imaginary line in the middle that divides it into left and right. We ‘cross the midline’ when we reach across the body with our arms and/or legs to complete tasks on the opposite side of our body. Crossing the body’s midline is an important developmental skill needed for many everyday tasks including fine and gross motor skills, coordination, self-care tasks and reading. 

Crossing the midline means we are using both sides of our brain to coordinate controlled and complex movements, such as, drawing a horizontal line across a page without switching hands, sitting cross-legged on the floor or picking up a puzzle piece using our dominant hand when the puzzle piece is on the other side. When a child spontaneously crosses the midline with their dominant hand, their ‘writing’ hand emerges.  

Difficulties with crossing the midline can often be seen when a child: 

  • Swaps hands during a writing, painting or drawing task. 
  • Becomes frustrated when completing fine-motor tasks. 
  • Typically uses their left hand for activities on the left side of their body and their right hands for activities on the right side of the body. 
  • Has difficulty with coordinating gross-motor skills e.g. crawling, skipping or star jumps. 
  • Rotates their trunk when reaching across the body. 
  • Has difficulty tracking an object from one side of their body to the other e.g. following text when reading.  

Skills needed to allow our body to cross the midline: 

  • Using both sides of our body simultaneously.  
  • Core stability and trunk rotation. 
  • Body awareness. 
  • Following multi-step instructions.  

Some activities to support crossing the midline: 

  1. Encourage the use of both hands in play e.g. rolling play dough with a rolling pin. 
  2. Hand and finger action songs e.g. Incy-wincey spider, or the wheels on the bus. 
  3. Position tasks to encourage crossing the midline.  
  4. Pop bubbles.  
  5. Balloon tennis: encourage your child to hold a racket/bat with two hands and allow them to bat balloons thrown to both sides.  
  6. Simon Says: encourage your child to touch opposite sides of their body. 
  7. Craft activities: threading or lacing, tearing paper, simple origami. 
  8. Place stickers on one arm and encourage your child to remove them with the opposite hand. 
  9. Play Twister.