Unbound MEDLINE

Clarifying distal axonal properties of the median nerve.

Abstract

INTRODUCTION
Although length-dependent axonal excitability changes have been reported in the median nerve, the mechanisms underlying these changes remain to be further clarified.
METHODS
Axonal excitability studies were performed on median nerve at the palm and wrist in 20 healthy controls, with responses recorded over the abductor pollicis brevis.
RESULTS
The strength-duration time constant was significantly shorter (palm: 0.35 ± 0.01 ms; wrist: 0.48 ± 0.03 ms; P < 0.001), whereas rheobase was significantly increased (palm: 2.90 ± 1.12 mA; wrist: 2.09 ± 1.11 mA; P < 0.05) at the palm. In addition, there was a significant increase in depolarizing threshold electrotonus at 90-100 ms (P < 0.001) and a reduction in S2 accommodation (P < 0.001) and late subexcitability (P < 0.001) at the palm. The changes in excitability were independent of factors influencing median nerve cross-sectional area.
CONCLUSIONS
The present study reveals significant length dependent changes in median nerve excitability which may reflect differences in intrinsic membrane properties.

Links

  • Publisher Full Text
  • Authors

    Moore D, Menon P, Vucic S

    Source

    Muscle & nerve 45:4 2012 Apr pg 492-9

    MeSH

    Action Potentials
    Adult
    Aged
    Anatomy, Cross-Sectional
    Axons
    Electric Stimulation
    Electromyography
    Female
    Hand
    Humans
    Male
    Median Nerve
    Middle Aged
    Muscle Contraction
    Muscle Strength
    Muscle, Skeletal
    Neural Conduction
    Potassium Channels
    Wrist
    Young Adult

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    22431081