Tonic Neck Reflexes

Tonic neck reflexes are a group of newborn reflexes, or primitive reflexes. Babies have some of these at birth and develop others shortly after. Healthcare providers look for these reflexes during exams to make sure your baby’s nervous system works correctly. These reflexes help your baby learn how to control their body movements.

The five tonic neck reflexes are:

• Asymmetric tonic neck reflex (ATNR)
• Symmetric tonic neck reflex (STNR)
• Neck-righting reflex
• Tonic labyrinthine reflex (TLR)
• Parachute reflex

What do tonic neck reflexes look like?

Each of the tonic neck reflexes has a distinct look and purpose. Babies automatically move their bodies in certain ways because of these reflexes. Moving automatically helps babies learn how to control their own bodies.

Asymmetric tonic neck reflex

The ATNR helps with coordination and movement. It’s also a key component for developing hand-eye coordination.

For this reflex, your baby’s provider will lay them on their back, arms to the sides and legs straight. They’ll then turn your baby’s head to one side.

The word “asymmetric” in the formal name means that each side of your baby’s body does something different. When your baby’s head turns to one side, the arm on that same side extends outward away from their body. At the same time, their leg on the opposite side bends at the knee. These movements make your baby look like a fencer posing for a duel. That’s why the ATNR is also known as the fencer’s posture or fencing reflex.

Symmetric tonic neck reflex

The STNR neck reflex gets its name from how it causes the same movements on both sides of your child’s body. It works along with the tonic labyrinthine reflex to help your baby learn to crawl.

To see this reflex, your child’s provider will hold your child belly-down on their knee. They’ll place one hand on your child’s back and use their other hand to lift your baby’s head upward.

Extending your baby’s neck that way should make both arms extend toward the floor. At the same time, both legs should bend at the knees, raising their feet toward the ceiling.

Tonic labyrinthine reflex

The TLR reflex works with the STNR to help your baby learn to crawl.

To see this reflex, your baby’s provider will place them flat on their back. In that position, your baby’s neck naturally extends. That activates the reflex, which is to extend their arms and legs.

You can see the opposite effect when you place a baby belly-down on the ground. Their neck draws down toward their chest, which activates the reflex. That makes their arms and legs, especially at the shoulder and hip, flex and curl inward.

Neck-righting reflex

This reflex helps babies develop the ability to roll from their backs to their bellies.

To test the neck-righting reflex, your baby’s provider will place them flat on their back with their arms and legs extended outward. They’ll then turn your baby’s head to one side and hold it there for 10 seconds. Your baby should rotate their whole body in the same direction as their head.

When tonic neck reflexes are a concern

Tonic neck reflexes should happen at certain times in your baby’s life. If they don’t happen as expected or if they don’t go away in children when they should, that can be an important clue that your child has a medical condition.

Most of the tonic neck reflexes eventually vanish. Experts call that reflex integration. It happens as babies learn to control their bodies. The better they get at moving around, the less they need the reflexes. When the primitive reflexes don’t go away as they should, experts call them persistent reflexes.

These time windows are general. Every child develops differently. If you’re concerned about these reflexes, your pediatrician can check and offer guidance.

Asymmetric tonic reflex

Babies should have this reflex at birth. It should vanish in children sometime between 4 months old and 6 months old. But sometimes, it can disappear as early as 3 months old or as late as 9 months old.

The ATNR has the clearest impacts when it happens at the wrong times. Babies who don’t have the ATNR reflex before 6 months old may have hypotonia (low tone) or a condition that causes it. Having it after 6 months old may signal a condition like cerebral palsy.

The fencing response is when the ATNR suddenly shows up in otherwise healthy people who get hit in the head hard enough to be knocked out. When that happens, it’s ALWAYS a medical emergency. That person needs immediate professional care, even if they quickly come to and say they’re fine.

Symmetric tonic neck reflex

The STNR appears when babies are between 5 months and 9 months old. The response should vanish by the time they reach 1 year old. It becomes a concern when children still have it after they turn 1 year old.

Infants who have the STNR for too long often have issues with posture while sitting or standing. They may also have trouble with hand-eye coordination.

Neck-righting reflex

Infants should have this reflex at birth. It should vanish by the time they reach 6 months old.

When children don’t have this reflex at birth and don’t develop it within their first month of life, that can be a sign of a developmental delay. If they still have it past 6 months old, it can also be a sign of a neurological issue.

Tonic labyrinthine reflex

Infants have this reflex at birth. It should vanish by the time they’re 3 and a half years old. If it doesn’t vanish by then, it can signal a neurological issue. Children with a persistent TLR often have:

• Trouble judging distances and movement speeds, making it harder to walk and move around
• Overly flexible (hypermobile) joints
• Posture issues and trouble holding their head straight
• Difficulties with spelling, math and telling time
• Trouble coordinating movements for multiple body parts, like those used for walking, running, swimming, etc.

Exercises that can help tonic neck reflexes

If you’re concerned that your infant is having issues with these reflexes, talk with their pediatrician. Your child’s pediatrician may recommend exercises, refer you to physical therapy or refer you to a child neurologist for further evaluation.