Brain-Based Solutions™ for the Tonic Neck Reflex
Taking Up the Fencing Posture (Part 2 of 5)
The neck receptors give rise to a primitive reflex – the Tonic Neck Reflex (TNR) – found in newborn humans. Books say that the TNR normally vanishes by the child's first birthday, but that is functionally and demonstrably untrue. The TNR persists throughout life and is a fundamental tool for neurological examination.
The TNR is fundamental to and inseparably fused with balance; they reinforce each other in their effects on the upper extremities and oppose each other in their effects on the lower extremities. However, the aspects of steadiness seem to be the more dominant reflex for lower extremity patterning.
The TNR arise via stimulation of joint receptors in the neck (especially around the atlantooccipital and atlantoaxial joints) when the head is inclined forward, backward, or sideward, or rotated to either side. That is, turning the head to the left should cause facilitation of the extensors on the side of head rotation and the flexors on the side opposite head rotation. This rule applies to both upper and lower extremities (See the illustration to the right). Conversely, the TNR response causes a functional inhibition of both the flexors on the side toward head rotation and of the extensors on the side opposite head rotation.
Linda (47yo) had been having lower back pain for the past 2 weeks. It started after lots of bending and twisting, then reaching overhead to stock the shelves in her store. She had also been having some vague whole-head headaches.
During Linda’s exam, both the psoas major muscles appeared to be working normally when manual muscle testing the lower extremities. However, relative to the TNR, the psoas major appeared to display a conditional facilitation on the side toward head rotation, and conditional inhibition on the side opposite head rotation. That display is opposite to that which would otherwise be expected, and therefore pathological.
It is essential to realize that muscle performance is a functional display of the central integrative state (CIS) of the nervous system. The CIS is an indication of the nervous system's readiness to respond, and it is predictable relative to what would be considered to be normal.
Relative to the TNR rule, we know that Linda’s original psoas display was other than that which would be expected to be humanly normal; it was pathological. Its dysfunction indicated that a main low back stabilizer was working contrary to its original programming, and that has a very high probability of indicating an upper cervical problem.
This functional TNR display indicated that Linda's low back stability was the result of inappropriate cervical receptor stimulation -- i.e., uncoupled cervical spinal motion. Further, it suggested that upper body performance may have been more primary than lower body movement; the lower body tends to follow the upper body.
In the absence of TNR influence the postural demands of bipedal stance would be impossible. While a person can certainly move around despite TNR dysfunction, their performance level is "other-than-human."
Further, the TNR is not an isolated part of the human neurological design. Subsequent to cervical joint mechanoreceptor stimulation, afferent signals also rise to the cerebellum, midbrain, and cortex. Faulty sensory input at these levels means a probable inability to presynaptically inhibit nociceptive reflexogenic afferents a subsequently related motor errors compromised autonomic concomitants, structural problems, and the conscious perceptive of pain.
TNR display does indeed persist beyond the toddler stage. It is a fundamental part of normal human movement and displays itself both functionally and dysfunctionally. The functional display encourages neurological stability while the dysfunctional display means certain performance error.
Palpation of Linda's lower cervical spine indicated pathological -- uncouple -- spinal motion. Challenging the cervical spine in one direction and treating it accordingly brought about the expected psoas display.
According to functional neurological principles, a bilateral psoas major dysfunction indicates the strong probability of an occipital fixation as opposed to a subluxation; the two findings are quite unique. Challenging the upper cervical spine and occiput, and treating the findings accordingly brought about the expected psoas display relative to the TNR stimulation.
If the tonic neck reflex were to disappear by a child's first birthday like many authorities believe, the human fabric would be missing an essential component to upright posture and functional stability.