This is a reflex test... It's called the Asymmetrical Tonic Neck Reflex (ATNR). This reflex should normally integrate (go away) by around 6 months of age. If it's still present later, it can affect posture, hand-eye coordination, and even reading and writing skills. You can check this on your child by having them in a "puppy push-up" position, gently turning their head side to side, and watching to see if their arms straighten or bend in response. For more reflex testing examples, DM us the word

Forearm Supinator Stretching