Soleus H-reflex to S1 nerve root stimulation.
H-reflexes in normals were elicited by percutaneous electrical and magnetic stimulation of proximal nerve roots at the cauda equina. H-M interval to S1 nerve root stimulation at the level of the S1 foramen was 6.8 +/- 0.33 ms, with side to side difference of 0.16 +/- 0.13 ms. Compression/ischemia of the sciatic nerve in the mid-thigh abolished the H-reflex to stimulation of the tibial nerve at the popliteal fossa when the H-reflex to S1 nerve root stimulation was preserved. The length of the S1 nerve root in human cadavers was measured to be 17.5 +/- 03 cm, providing an estimated dorsal root conduction velocity of 67.3 m/s and a ventral root conduction velocity of 54 m/s. We conclude that the H-M interval to S1 root stimulation can provide reliable measures of conduction within the spinal canal including proximal afferents, anterior horn cells and ventral roots.
Zhu
Y
Y
Department of Neurology, University of California, Irvine, USA. zhuyu@vax.cs.hscsyr.edu
Starr
A
A
Haldeman
S
S
Chu
J K
JK
Sugerman
R A
RA
D000328:Adult; D002420:Cauda Equina / Q000502:physiology; D004558:Electric Stimulation; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D007511:Ischemia / Q000503:physiopathology; D008280:Magnetics; D008875:Middle Aged; D011930:Reaction Time / Q000502:physiology; D012584:Sciatic Nerve / Q000098:blood supply; D013126:Spinal Nerve Roots / Q000502:physiology*