Symmetrical tonic neck reflex
Symmetrical tonic neck reflex (STNR) is a bridging or transitional brainstem reflex that is an important developmental stage and is necessary for a baby for transition from lying on the floor quadruped crawling or creeping.[1]
In order to be able to do this the baby needs to have been successful in unlinking the automatic movement of the head from the automatic movement of the arms and legs.
Onset of STNR occurs between 4–6 months and its integration occurs by 8–12 months.
Testing
It can be tested by placing the child in quadruped position on the floor and passively flexing the head forward and then extend it backwards. The expected response would be forward head flexion producing flexion of the upper extremities and extension of the lower extremities while extension of the head will produce extension of the upper extremities and flexion of the lower extremities.
Significance
This reflex can help the child to come to quadruped or crawling position but does not allow crawling because when the neck flexes forward, the upper limbs flex and lower limbs go into extension.
This reflex is not normally easily seen or elicited in normal infants but may be seen in an exaggerated form in many children with cerebral palsy.