Specific Potentialities of the Subluxation Complex
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This is Chapter 7 from RC’s best-selling book:
“Basic Principles of Chiropractic Neuroscience”
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Chapter 7: Specific Potentialities of the Subluxation Complex
This chapter describes the primary neurologic implications of subluxation syndromes, either as a primary factor or secondary to trauma or pathology, within the cervical spine, thoracic spine, lumbar spine, and pelvic articulations.
Studies reported by Drum, Hargrave-Wilson, Kunert, Burke, Gayral/Neuwirth, and others have shown that a subluxation complex, often leading to spondylosis, can effect a wide variety of disturbances that may appear to be disrelated on the surface. Most of the remote effects can be grouped under the general classifications of nerve root neuropathy, basilar venous congestion, cervical autonomic disturbances, CSF pressure and flow disturbances, axoplasmic flow blocks, irritation of the recurrent meningeal nerve, the Barre-Lieou syndrome, and/or the vertebral artery syndrome.
This chapter describes many causes for and effects of a spinal subluxation complex. In clinical practice, however, causes and effects are rarely found as isolated entities. Several factors will usually be involved and superimposed on each other.
Innervation of the Spinal Dura
It has long been known that the spinal dura mater has an intrinsic nerve supply. Spinal meningeal rami are derived from gray communicating rami and spinal nerves. The spinal nerves contribute sensory fibers to the meningeal rami. Several meningeal rami enter each IVF, and most are located anteriorly to the sensory ganglia within the IVF.
Bridge found that these intrinsic nerve fibers reach the anterior surface of the dura by three main courses. Here the nerves divide into ascending and usually longer descending filaments that run longitudinally and parallel on the dural surface, and a considerable amount of nerve overlaps from adjacent segments. Finer filaments penetrate the dural substance where they subdivide.
Kimmel reported that most of these fibers penetrate the dura near the midline, while others enter laterally near the exiting spinal nerve roots. At each segment level, two or three nerves enter the spinal dura mater and contain only small nerve fibers. In contrast, Edgar/Nundy could determine no definitive nerve endings, but the nerves could be traced to the posterior aspect of the spinal dura. These observations help to clarify the wide distribution of back pain that is often found following protrusion of a single IVD.
Cervical Dura Attachments
Sunderland states that the nerve sheaths in the cervical region are not firmly attached to their respective foramina. Only the C4 C6 cervical nerves have a strong attachment to the vertebral column, and this is to the gutter of the vertebral transverse process. He believes that these observations have relevance to any local lesion that may fix, deform, or otherwise affect the nerve and its roots to the point of interfering with their function, and they also may be important to traction injuries of nerve roots.
The sympathetic nervous system, in conjunction with a sensory root compression or independently, plays a role in the interpretation of pain. Compression of the recurrent meningeal branch of the spinal nerves, for example, results in a wider distribution of pain and muscle spasm than the local pathology may indicate.
Many authorities attribute most lumbosciatic pains to IVD faults. The typical disc lesion is thought to produce restrictions in the dura mater during straight-leg-raising or neck flexion tests.
Cyriax believes that lumbago does not arise from tissue that has undergone degeneration (eg, myofibrosis) because the incidence of backache falls by two-thirds between the ages of 60 and 70 and has almost ceased by the age of 80. He attributes the pain to the impingement of discoid material on the dura mater or its root sleeve. He feels that the syndrome is initiated by an attack of internal derangement at a low lumbar IVD as the result of a momentary posterior displacement of a movable piece of intra-articular fibrocartilage. The prolonged subsequent pain is believed to be caused entirely by bruising of the dura mater.
In describing the relationship of structural pathology to the nerve root, Kirkaldy-Willis takes a broader view. He states that the nerves of the lumbar spine may be entrapped:
(1) at the back of the IVD,
(2) laterally in the central canal,
(3) in the cauda equina,
(4) more laterally in the nerve canal, and
(5) posteriorly in the zygapophyseal joints.
Changes at these sites can produce dysfunction, disc herniation, instability, lateral entrapment, central stenosis. However, he does state that the pain from a disc lesion or stenosis may come from irritation and inflammation of the dura. The motor loss in these lesions may be attributable a reflex inhibition and vascular insufficiency rather than from nerve compression.
Nerve Root Compression/Irritation
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