On so-called paresis of divergence.

  • Berry, George Andreas, 1853-
Date:
[1901]
Catalogue details

Licence: In copyright

Credit: On so-called paresis of divergence. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    due to,any change which takes place in the innervation or -in the physical state of the antagonist. With the more or less complete disappearance of tonic innervation in an external rectus, for instance, a greater or less pre- ponderance of action takes place in the internus'whose tonic innervation is unimpaired. Thus is developed the position of convergence which in many cases characterises the position of rest in paralysis or paresis of-the sixth nerve. The term secondary contracture Js therefore, I believe, and have always maintained, a mi.snom'er. -It is one of the many terms expressive of conceptions borrowed from muscular changes in other parts of the body.. It is very generally, I think, lost sight of-that the eye muscles differ in various ways, both anatomically and physiologi- cally from the skeletal muscles. In conclusion, I may say that I have brought forward this case, a typical example of what, in my-experience, is a rather rare affection, firstly to prove that the nature of the diplopia is an evidence of the pathological convergence being diminished on lateral fixation. Again 1 wished to offer an explanation of this symptom. As I have ex- plained, it can only be caused by the influence of habit. Finally, and more particularly, I wished to make it clear that the correct diagnosis is spasm of convergence, and not paresis of divergence, any more than a persistent associated lateral deviation of both eyes is to be looked upon as an expression of paresis of associated movement in the opposite direction. Both conditions, moreover, are, in my experience, always transitory, whereas both paresis of convergence and of associated lateral movement are often permanent. Printed liy T. and A. Constable, (late) Printers to Her Majesty at the Edinburgh University Press