"Tracheal buckling is often more prominent during expiration, but not usually completely eliminated on inspiration. Marked extension or rotation of the head may also reduce its conspicuity5."
"Tracheal buckling is a normal finding in young infants when the trachea is more flexible. There is typically deviation of the trachea anteriorly and to the right (up to 90°). Normal deviation to the left is observed only when aortic arch is located to the right of the trachea 4. Any other configuration (i.e. to the left or posteriorly) should raise the possibility of underlying pathology."