At the completion of this chapter, the reader will be able to:
Summarize the various types of neurodynamic examination and mobilization techniques.
Describe the proposed mechanisms behind the neurodynamic examination and mobilization techniques.
Apply knowledge of the various neurodynamic mobilization techniques in the planning of a comprehensive rehabilitation program.
Recognize the manifestations of abnormal nervous tissue tension and develop strategies using neurodynamic mobilization techniques to treat these abnormalities.
Evaluate the effectiveness of a neurodynamic mobilization technique when used as a direct intervention.
Neurodynamics is the study of the mechanics and physiology of the nervous system. The nervous system is an electrical, chemical, and mechanical structure with continuity between its two subdivisions: the central and peripheral nervous systems (see Chapter 3). In addition to permitting inter- and intra-neural communication throughout the entire network, the nervous system is capable of withstanding mechanical stress as a result of its unique mechanical characteristics. Nervous tissue, a form of connective tissue, is viscoelastic. This viscoelasticity allows for the transfer of mechanical stress throughout the nervous system during trunk or limb movements. This adaptation results from changes in the length of the spinal cord1 and the capacity of the peripheral nerves to adapt to different positions. The peripheral nerves adapt through a process of passive movement relative to the surrounding tissue via a gliding apparatus around the nerve trunk.2,3 Three mechanisms appear to play an important role in this adaptability3:
- Elongation of the nerve against elastic forces. In normal daily movement, nerves may slide up to 2 cm in relation to surrounding tissues and contend with a strain of 10%.4
- Longitudinal movement of the nerve trunk in the longitudinal direction.
- An increase and decrease of tissue relaxation at the level of the nerve trunk.
According to Millesi,3 the efficiency of this mechanism partially depends on the capacity of the loose connective tissue around the nerve (adventitia, conjunctiva nervorum, perineurium) to allow any traction forces to be distributed over the whole length of the nerve.3 If this distribution of forces is compromised, an unfavorable rise in traction forces can occur at certain segments, depending on the anatomic site (see next section).3
The role that tension on the neural tissue plays in pain and dysfunction has been studied for over a century. During this time, a number of specific tests have been designed to examine the neurological structures for the presence of adaptive shortening and inflammation.5–7 The more common of these neurodynamic mobility tests are described in this chapter.
The spinal dura (see Chapter 3) forms a loose sheath around the spinal cord from the foramen magnum to the level of the second sacral tubercle. From there it continues as the filum terminale to the end at the coccyx. Laterally, the dura surrounds the exiting spinal nerve roots at the level of ...