Functional Electromyography by Loren M. Fishman & Allen N Wilkins

Author:Loren M. Fishman & Allen N Wilkins
Language: eng
Format: epub
Publisher: Springer US, Boston, MA

Signs

When it comes to signs, we have found that the straight leg raise (SLR) is generally positive, but not at all specific. We generally take it as positive when there is a 15° side-to-side discrepancy, or absolute value below 60° in bilateral cases. It may raise suspicion of piriformis syndrome if the pain SLR generates is in the buttock rather than the lower back, and if there is no contralateral pain of any kind. But the SLR is neither a necessary nor a sufficient condition; as an indicator of piriformis syndrome, it is not really very persuasive. We have definitely seen cases with negative straight leg raise.

Weakened abduction of the flexed thigh, first described in the Western Journal of Medicine by Pace [8], is certainly the most commonly positive sign in piriformis syndrome and a strong indicator of its presence. Since the piriformis muscle is a tertiary abductor of the flexed thigh, the weakness may be due to reflex inhibition of abduction mediated at the spinal level rather than any actual weakness of the piriformis muscle. In fact, its strength in compressing the sciatic nerve appears to be the pathogenetic mechanism.

Buttock pain with passive adduction of the flexed thigh, first described by the Norwegian neurosurgeon Solheim [16], is also sometimes observed in piriformis syndrome. The same maneuver may often bring pain in the hip and inguinal region, but those are quite different, and are usually due to trochanteric bursitis and hip pathology, respectively.

Sometimes these maneuvers or pressure in the region of intersection of the piriformis muscle and the sciatic nerve actually produce sciatic-like symptoms. This, of course, is highly suggestive of piriformis entrapment of the sciatic nerve. It is also a clinical rendition of the functional electrodiagnostic test that forms the heart of this chapter.

Download

Copyright Disclaimer:
This site does not store any files on its server. We only index and link to content provided by other sites. Please contact the content providers to delete copyright contents if any and email us, we'll remove relevant links or contents immediately.