LO puts himself in the position pictured below. His head is all the way back and his back is bent inward (opposite of arch). He did this one time in front of his pediatrician at his one month check up while being touched and examined. The pediatrician freaked out. He isn't in pain and seems to do it when asleep and awake. When I move him back to a more linear position he puts himself back in the curve.

Is this normal? Does your LO do the same?