What is the Symmetric Tonic Neck Reflex (STNR)?

by Jessica Hill, COTA/L August 20, 2021

What is the Symmetric Tonic Neck Reflex?

The Symmetric Tonic Neck Reflex (STNR) is one of many infant primitive reflexes - an involuntary movement pattern that we are all born with. However, the STNR is not actually present until after birth - it appears between 6 and 9 months of life. This is due to its correlation with the TLR (Tonic Labyrinthine Reflex) - as an infant begins to integrate the TLR, the STNR emerges to help progress to the next phase of development, crawling.

The STNR divides the body in half - lower half and upper half. There are also two movement patterns - flexion and extension. As the infant moves from prone (on belly) to quad (on hands and knees), they will begin to extend their neck - look up, and flex their neck - look down. These movements will then elicit a response in the upper and lower limbs. During neck extension, the arms will straighten while the legs will flex/bend. During neck flexion, the opposite will occur - the arms will flex/bend while the legs will straighten - moving the infant into a somewhat down dog position.

The life span of the STNR is very short - just 2-3 months. That is because as the infant moves from prone to quad, they will begin to start learning how to crawl. As they learn to crawl, the STNR will start to integrate. 

The “rocking” movement that infants do while on hands and knees, right before they begin to crawl? That may be the STNR beginning to integrate! The STNR should be fully integrated - no longer present - by 11 months of age.


How does the STNR integrate?

Although there is no one scientific method to ensure full primitive reflex integration, there are some things to consider when discussing the integration of the STNR.

Primitive reflex integration

Let’s talk about sensory integration. By providing an infant with different types of sensory stimulation, new neural pathways will be developed in the brain, thus stimulating new movement and cognitive development. An article on sensory integration discussed that the engagement in sensorimotor activities promoted adaptive behaviors via neuroplastic changes - simply put, by experiencing different types of sensory activities, our brains can change and thus promote new behaviors!

So what types of sensory activities should you provide to your newborn infant? Keep it simple!

  • Natural movement is always a fantastic option - instead of carrying your newborn in a carrier or stroller, use a wrap to carry your newborn on your body to provide more natural movement.
  • Carry your infant in different positions - on their tummy, back, side, etc. This will provide movement in different planes.
  • Tummy time. We’ve all heard it over and over again - tummy time is a must! A systematic review from 2020 identified that tummy time was positively associated with gross motor and total development. But how do you start tummy time with a newborn? Simply laying your newborn on your chest, on their tummy, is a great place to start. Then incorporating tummy time into everyday play will begin to establish a routine and improve tolerance in the long run.
  • Placing toys in different planes that baby has to reach for - both sides of the body, in front of the body, behind, etc. Also, promote visual tracking - thus facilitating head turns - by moving preferred toys around the body, slowly and at eye level or slightly above.
  • Once your infant has moved from tummy time into a pre-crawling position (on hands and knees), play different visual tracking games. Move preferred toys slowly up above their head and down on the floor, facilitating neck extension and flexion.
  • Also, at this time, begin placing motiving toys just a couple of inches away so they can start reaching and attempting to move forward.
  • Don’t skip crawling! Use tunnels to promote more crawling, crawl on different surfaces, and ensure that both hands and knees are in contact with the ground.
  • A variety of sights, sounds, smells, and tactile experiences. The more variety and the more frequent, the better!

Because every infant is different and every experience is different, there’s no one way to guarantee that the STNR will be successfully integrated by 11 months of age. However, by using the above strategies, you can feel more confident that your baby is getting the sensory experiences necessary for potential primitive reflex integration.


What factors can contribute to an unintegrated STNR?

Potential factors for unintegrated primitive reflexes, including the STNR are:

  • Stress during pregnancy
  • Substance abuse during pregnancy
  • Caesarean section birth
  • Brain damage during labor
  • Premature and low birth weight
  • Significant illness during the first year of life
  • Insufficient stimulation and tummy positioning
  • Lack of free movement time on the floor
  • Stressful environment
  • Not enough nourishment/insufficient weight gain

Additionally, if a child has successfully integrated their primitive reflexes, a sudden or chronic bout of trauma, stress or injury can re-activate these reflexes.

While there is no guarantee for reflex integration, there are contributing factors to take into consideration if your child has an unintegrated STNR.


What an unintegrated STNR looks like

As previously mentioned, the STNR is linked with the TLR as well as has a direct correlation to muscle tone, upper and lower body movements, and head movements. These connections go even further to include vision and ocular motor skills, balance, and coordination.

Symptoms related to an unintegrated STNR in older children are:

  • Minimal to no crawling
  • Unusual/awkward crawling
  • Poor posture
  • W-sitting
  • Lays head on desk during focus tasks
  • Decreased hand-eye coordination
  • Challenges with near-far point tracking
  • May seem clumsy, poor overall coordination
  • May be a messy eater
  • Challenges with attention and focus
  • Challenges with reading and writing
  • Difficulty copying from the board
  • Signs of Dyslexia


Watch How to Assess for Retained STNR

What can I do if my child has an unintegrated STNR?

If your child exhibits any of the above symptoms/challenges, the first step is to talk with your pediatrician. Discuss your concerns - if your pediatrician is familiar with primitive reflex integration, they may already have a plan of action ready. If your pediatrician is unfamiliar with primitive reflex integration, feel free to share what you've learned! If you ever feel uncomfortable or that your concerns are being pushed to the side, don’t be afraid to seek out a new pediatrician.

Many Occupational Therapists (OT) are trained in primitive reflex integration techniques. Seek one out! Talk with friends and family members to see if they know anyone specific. Use Facebook groups and Instagram to find someone who has training. Physical Therapists (PT), craniosacral therapists, and chiropractors may also have knowledge of primitive reflex integration. It can take some time to locate the right professional, so don’t give up!

Meanwhile, there are some different exercises and play activities that you can incorporate into your child’s daily routine that can help promote the integration of the STNR.

For babies, decreasing the amount of waking time spent in containers is the best way to integrate the STNR. These are things like bouncers, jumpers, walkers, etc. When baby is awake, provide natural movement opportunities, plenty of tummy time, and opportunities to visually track and reach for objects in their environment. If safety is a concern during tummy time or pre-crawling, opt for something like a pack and play instead of a container that doesn’t allow for natural movement.

If your child is young, under three years old, focus on developmental movements.

  • If your infant is struggling to put weight through their arms, thus causing challenges achieving and maintaining a quad (hands and knees) position, place a rolled-up towel under their chest for extra support.
  • When your infant is in quad, turn on some music and help them “dance” - that rocking movement forwards and backwards. You can place your hands at their hips to help facilitate this.
  • Get them crawling! Once your infant can bear weight through their arms, they can begin attempting to crawl towards motivating objects.
  • Use tunnels to facilitate crawling. Roll balls and push toys through, have motivating toys on the other side, etc. Don’t have a tunnel? That’s ok! Make your own by placing a blanket over 2 or more objects.

If your child is older, you can still focus on the same developmental movements and increase the challenges, as well as try some other activities.

  • Use obstacle courses as a way to get your child crawling.
  • Complete a visual chart activity - place one visual chart on the wall at eye level (while positioned in quad) and one visual chart between on the hands on the floor. Alternate reading between the two charts, thus completing neck flexion and extension. Bring attention to any arm and leg movements as needed.
  • Cat-Cow yoga movement. You know the one! Complete slowly and maintain arms and legs stationary.

If your child is struggling with some of the signs/symptoms associated with an unintegrated STNR, try some of these strategies:

  • Poor posture and/or w-sitting
    • Teach your child to sit in more functional positions such as a side-sit (criss-cross sitting may be very challenging if your child is accustomed to a w-sit).
    • Sit on a therapy ball to activate the core muscles to decrease a slouched position.
    • Provide more rest breaks during physical activity. Poor posture is often accompanied by fatigue.
    • Engage in core strengthening tasks using a therapy ball, jumping and climbing, yoga stretches, etc.
  • Laying head on desk, challenges with copying from the board, challenges with handwriting
    • Try alternative seating options to improve posture.
    • Try using a slant board to decrease the need to look down (neck flexion) and up (neck extension) as often.
    • Similarly, provide items that need to be copied next to the child instead of up and away from the child.
    • Talk with your child’s teacher to discuss strategies such as decreasing the amount of required writing.
  • Messy eating
    • During mealtime, use a mirror to bring attention to what the hands and mouth are doing, notice where food is, etc.
    • If oral motor concerns, swallowing concerns, or other safety concerns while eating are noted, talk with a Speech-Language Pathologist or a Feeding Specialist.

One last note

As you continue on your path through primitive reflex integration, keep in mind that your child is unique and there's nothing wrong with them! Even if they have an unintegrated STNR and seem to be struggling more than other children, your job is to help guide them along the way and provide as much support as possible.

You and your child are doing the best you can with what you have, so keep researching and keep trying new things until you find what works. Even then, keep searching because what works now might not work forever, especially as your child grows and develops through different seasons of life!

Check out our video about Primitive Reflexes in Infancy




Want to listen to more information on the STNR? Check out our podcast episode on it!

Want to become an expert on Primitive Reflexes?

Be sure to check out our full Primitive Reflex Integration Training!


Check out our video about What is the Symmetric Tonic Neck Reflex (STNR)?

Jessica Hill, COTA/L
Jessica Hill, COTA/L

Jessica Hill, COTA/L, CPRCS is Harkla's in-house Certified Occupational Therapy Assistant (COTA) and Certified Primitive Reflex Clinical Specialist. She has been working with children for over 6 years in outpatient settings. Jessica specializes in creating easy-to-digest, actionable content that families can use to help their child's progress at home. Jessica is the in-house expert, content creator, and one of the podcast hosts at Harkla! To learn more about Jessica, visit the Harkla About Us Page. Make sure to listen to her weekly podcast, All Things Sensory by Harkla for actionable, fun advice on child development.

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