Text-book of nervous diseases for physicians and students / by H. Oppenheim.
- Date:
- 1911
Licence: In copyright
Credit: Text-book of nervous diseases for physicians and students / by H. Oppenheim. Source: Wellcome Collection.
Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.
31/1480 page 7
![Exaggeration of muscular tonus (stiffness, rigidity or spastic condition of the muscles) can be recognised, secondly, from exaggeration of the tendon phenomena. On account of the close, though not absolute and constant, relation of the tendon phenomena to the muscle tonus, it is advisable to examine them directly after examination of the passive mobility of the limb. Examination of the Tendon Phenomena.—By this symptom, which Westphal^ and Erb ^ described, independently of each other, in 1875, we understand muscular contractions which are induced by a mechanical stimulation of a tendon. The most important of these is the knee jerk (also called the patellar phenomena or reflex). This is always present in healthy persons, and its absence has great diagnostic singificance. Erb regards this symptom as a simple reflex. Westphal held that the knee jerk de]iends on a direct excitation of the muscle which is maintained in a state of tonus through reflex influences. Results of later investigation favour the reflex-theory (Sternberg, Jendrassik, Scheven and others). Recently several vfriters have given their support to Westphal's view (Muskens, Sherrington). In order to produce the knee jerk, the following method is the best : the leg of the patient, Avho lies on his back, is bared, placed at an obtuse angle and supported by the left hand of the examiner at the popliteal space, the heel resting on the bed. The right hand first feels for the patellar tendon, if it does not at once stand out distinctly, and then gives it a sharp tap with the percussion hammer. The thigh should first be watched to ascertain whether the extensor cruris muscle becomes tense. The effect of this tension is, when it is sufficiently strong, an extension of the leg. But it is advisable to place less weight on this factor (as it does not alwaj's appear) than on the muscular contraction. This should not be confused with a simple vibration of the skin and muscle substance, which is directly communicated to them from the tendon. If the tap on the tendon has not elicited the contraction, then we should discover whether there is not an active or unconscious voluntary muscular tension. This will be rapidty recognised if the supported leg does not fall back to the bed immediately on the supporting hand being taken away. Relaxation of the tension should then be induced according to the rules given above, the examination being modified hy allowing the patient to cross one leg over the other. If this has not the desired effect, then Jendrassik's method va.a,y be used : the patient is asked to fold his hands and at a word to make a forcible effort as if to pull them asunder, without, however, really doing so. At that moment the tendon is tapped. If this does not succeed in eliciting the knee jerk then we should examine the patient in a sitting position, which is best done if he sits on a table and allows his legs to hang free. It has also been proposed that during examination of the knee jerks other stimulations should be applied, such as the prick of a needle, the throwmg of a bright light on the retina. These act not only by distracting the attention of the patient, but apparently also by increasing the nerve conduction. It is further recommended that the patient sliould breathe deeply, read aloud, etc., during the examination. I have, however, always been able to dispense with these and similar procedures. A.j.P., Bd. iv. and Bd. v. ^ A. f. P., Bd. V. See also specially the monograph of Sternberg, Die Sehnenreflexe, etc., Leipzig u. Wien, 1893 ; also Scheven, .4. /. d. g. Phys., 117.](https://iiif.wellcomecollection.org/image/b21981590_0031.jp2/full/800%2C/0/default.jpg)
