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ASSESSING SCIATIC NERVE GLIDE PART 2 Nerves are not wires. Although both nerves and wires transmit electrical impulses, nerves are much more than electrical cables. Nerves, because they are living, perceptive, and sentient structures, are sensitive to being crowded, confined, or overstretched. When the sciatic nerve is entrapped or irritated, pain in the low back, buttock, and lower limb is the result. As explained in the last article ("Assessing Sciatic Pain," July/ August 2011, page 110), sciatic pain arises from either axial origins (typically at the spinal nerve roots), or from appendicular causes (distal entrapments in the buttocks, hip, or leg). In this article, I will list some of the most common appendicular sciatic nerve entrapment sites, and describe one way of determining where appendicular entrapment may occur. In the next article, I will introduce hands-on methods from Advanced-Trainings.com's Advanced Myofascial Techniques series that have proven both safe and effective for easing appendicular sciatic pain. UNDERSTANDING NERVE ENTRAPMENT In order to understand sciatic nerve entrapment, it is helpful to review some important features about nerves in general, and the sciatic nerve in particular. The neurons that make up the sciatic nerve are the longest in the body—originating in the spinal cord and extending to the hip, leg, and foot. Like all peripheral nerves, these neurons are wrapped and bundled within various layers of connective tissue, the outermost layer being the epineurium (Images 1 and 3), which is a continuation of the arachnoid and dural layers surrounding the central nervous system. The connective tissues of a nerve: 1. Help maintain its internal electrochemical environment. 2. Carry the nerve's intrinsic blood vessels and sensory nerves. 3. Give the nerve its structure, tensile resilience, and elasticity. Impingement (compression or tension) on the nerve impairs all three of these functions, causing internal inflammation of the nerve, reducing its blood flow, and diminishing its ability to glide and stretch. Elastic glide is particularly relevant to our work. The long neurons within the sciatic nerve stretch an additional 3½–5 inches with normal hip, knee, and ankle motions.1 amount of gliding movement between the epineurium and the surrounding intermuscular septa, muscle sheath, and supporting fasciae. A nerve gliding within these surrounding connective tissues can be compared to a tendon's movement within its surrounding bursa. As with other connective tissues, the epineurium sheath around a nerve may itself become adhered or This causes a significant The epineurium (pink) and its finer enervating sensory filaments (nervi nervorum, yellow), which are involved in pain of the nerve itself. tethered to surrounding structures; it may also become hardened and thickened from strain or injury. Since this protective sheath contains blood vessels that supply the nerve, adhesions or hardening of the epineurium can choke the nerve's circulation, worsening the internal inflammation. Impingements on the nerve sheath may also cause pain directly—the sheath itself is highly enervated by smaller sensory nerve filaments (the nervi nervorum, Image 3) that tune in to your practice at ABMPtv 111 Although living nerves are much more complex than wires, a nerve's connective tissue layers are analogous to the layered wrappings around an electrical cable. Image courtesy www. periodictable.com. Used with permission.