Birefringence and Contractile Power of Muscles During Atrophy Due to Upper Neurone Lesions or Tenotomy

Abstract

Summary

Although in muscular atrophy, either due to final or upper neurone lesions, or due to tenotomy, there is a distinct weight loss after 9 to 10 days, the muscles have at that time still the same contractile power per weight unit and the same birefringence as normal muscles. But 3 to 5 weeks after onset of the atrophy, only muscles atrophying due to upper neurone lesions or to tenotomy have still the contractile power per weight unit and the birefringence of normal muscle. However, for denervated muscle, contractile power and birefringence are distinctly diminished at that time. Only in the latter type of atrophy does the submicroscopic crystalline structure, so essential for the contraction process, become seriously impaired.