Volume 1

Textbook of nervous diseases for physicians and students / Translated by Alexander Bruce.

  • Oppenheim, Hermann.
Date:
1911
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Textbook of nervous diseases for physicians and students / Translated by Alexander Bruce. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    physiological limit (Fig. 1); and (2) usually, though not constantly, by a diminution or absence oj tendon reflexes. If the knee jerks cannot be elicited under any of the conditions described ahove, in any of the leg positions, with the attention distracted, and even with the aid of Jendn'issik's method, then we are justified in regarding them as abolished, as absent. But before this result has any diagnostic value, we must determine whether there is not a mechanical cause. Disease of the knee-joint, dislocation of the patellar tendon, an ununited fracture of the patella may be present. Indeed a great accumulation of fatty tissue, in which the tendon is embedded, or a severe oedema may be the cause of the absence of the contraction. There are also some individuals in whom the tendon is so short and so deeply placed, that it can hardly be affected by the hammer. If it is very flaccid and lies very deep, the reflex is sometimes only elicited after the leg has been flexed* to an acute angle. I have sometimes had to resort to this artifice in cachectic individuals. Pro. 1.—Muscular hypotonia and its influence on passive motility (after Dejerine). Absence oj the knee jerk is a sign of the greatest value in diagnosis. Although Westphal's discovery relates only to the condition of this symptom in a certain disease (tabes dorsalis), yet it is so firmly associated with his name, that loss of the knee jerk is generally known as Westphal's sign. It should alwa3*s be remembered that the condition of the tendon reflexes is influenced not only by diseases of the nervous system, but also by other factors. Thus the knee jerk cannot as a rule be elicited in deep narcosis, or in complete unconsciousness. Great rise of temperature majr have the same effect (Petitclerc, Sternberg). Severe exhaustion from excessive physical exertion may also lead to temporary loss of the tendon reflexes (Auerbach,1 Edinger, Knapp and Thomas. Oeconomakis 2). It is very difficult to recognise and to estimate diminution of the knee jerk. When it can be elicited only to a slight degree, even by means of Jendn'issik's method, and when the contraction is limited to single segments of the quadriceps, to the vastus interims, for instance, then there is a pathological modification. In unilateral diseases, com- parison with the unaffected side facilitates the decision. It has already been shown that the same factors determine the 1 N. C., 1905. 2 N. C, 1907.