SacroCoccygeal Syndrome and the SacroCoccygeal Reflex

By Dr. Chris Kemper

SacroCoccygeal Syndrome

  1. Loss of Lumbopelvic Flexibility
  2. Loss of Motor Strength
  3. Palpable loss of Coccyx Segmental Motion

SacroCoccygeal Reflex

The neurologic mechanisms comprising the SacroCoccygeal reflex could involve both central and cord reflexes including the vestibular, arthrokinetic and Golgi tendon responses. Together, the proposed SacroCoccygeal reflex elicits two distinctly different pathological clinical effects:

  1. Hypertonicity of the lumbopelvic anti-gravity musculature: The Vestibular nuclei transmit strong excitatory signals to the antigravity muscles when as little as 1/2 of a degree of head disequilibrium occurs from the precise upright position6 (ibid). In such an event we know, by studying balance mechanism pathways, inhibition from the medullary reticular nuclei is rapidly overcome by the pontine reticular and vestibulospinal nuclear function6 (ibid) excitatory in nature, and necessary for balance. Could an already excited and facilitated anti-gravity erector group, necessary for erect posture be further potentiated by a coccyx dysfunction-induced cord stimuli?
  2. Hypotonic motor deficit of sacral and coccygeal spinal nerves induced by excessive inhibition, triggered by massive sacrococcygeal hypomobility-induced midline pelvic floor muscle tension: Much of the pelvic floor musculature’s diaphragm-like motion is altered when trauma causes coccygeal angulation, displacement and particularly sacrococcygeal hypomobility and can affect muscle fiber length and tension. Golgi tendon organs are located in the muscle tendons and transmit information about tendon tension or rate of change of tension6 (ibid). This is true of all skeletal muscles.

Loss of normal coccygeal motion can severely limit and impede pelvic floor diaphragm-like compression and distension and could logically affect Golgi tendon organ response in regional musculature. Golgi tendon organs respond dynamically through a reflex from dorsal horn to interneuron to anterior horn and back to directly inhibit the individual muscle the Golgi tendon apparatus serves6 (ibid). When tension on muscle (pelvic floor) and therefore on the tendon become extreme, the inhibitory affect from the tendon organ can be so great that it leads to a sudden reaction in the spinal cord that causes instantaneous relaxation of the entire muscle (not just the spindle served by the initiating Golgi). This affect is called the lengthening reaction6 (ibid). This powerful Golgi tendon reflex, transmitted through the cord, could be the peripheral source for the profound motor hypotonicity, weakness or motor deficit associated with sacrococcygeal hypomobility.

Summary:

Local Golgi organ response and central reticular affects related to coccygeal dysfunction are one possible explanation of a neuromechanical mechanism that could explain observed measurable changes in hip or thigh rotator strength and trunk flexion. If any part of this hypothesis is true, other questions become immediately pertinent such as:

  • How can researchers measure the extent to which the hypothesized abnormal dural tension may potentiate a central facilitation or a local inhibition?
  • How much linear or axial downward pull, upon the neural`tissues, can an increase in the radius of coccygeal motion or displacement exert?
  • What other processes may account for the proposed SacroCoccygeal Reflex and its clinical presentation?

More research is needed to precisely measure coccygeal function and dysfunction and its apperant relationship to the pelvic floor structures, the filum, thecal sac and conus medullaris.

Respectfully submitted.

References

6. Guyton and Hall. Textbook of Medical Physiology. WB Saunders Company (An imprint of Elsevier) 2007. Pages 690-96.