Examination.—To devise a clear plan of procedure for operations we must carefully separate the paralyzed from the paretic and healthy material. In order to examine the condition of the single muscles we possess different methods.
We will be able to make a tentative diagnosis from the position of the limb, from its spout aneons motions, and from palpation of paralyzed and atrophic muscle. In older children the voluntary motions, which we let them carry out to the full extent of each single muscle, will instruct us in the best and easiest way about the extent of the deficiency. The impulse of the will is more exact than electrical stimulation. The surmounting of resistances will inform us about the weakening of the motor strength (fist pressure, resistance movements).
For these examinations we must possess an exact knowledge of the anatomy of the muscles and nerves.
Besides these methods we also possess an excellent means in electro diagnosis, by which we can measure the irritability of the muscle through the muscle as well as through the nerve.
The time of the appearance of the opening and closing contractions has led to the formulation of Huger's law of contractions.
In the normal muscle the cathode closing contracture prevails over the anode closing eontracture (C.C.C.>A.C.C.).
If the connection between the muscle and its end-nerve with the centre should be interrupted, and voluntary impulses are no longer transmitted, then the electrical irritability will also sink soon and instead of the normal short contractions we get the well-known sluggish slow vermiform fibrillations; the cathode closing contraction diminishes, the anode closing contraction prevails, A.C.C.> C.C.C. (reaction of de generation). Finally, only a very slight anode closing contraction will be left, "but years may elapse before the galvanic irritability in the degenerated muscle dies out entirely" (Erb).
The points from which the muscle may be excited through the nerve are well known, and we are therefore able to determine by the quantity of the irritability by eleetro-diagnosis not only paralyses but pareses and lessened strength as well. This we can do easily in adults and also
in older sensible children.
In smaller children the difficulties increase, owing to their ness, the smallness of surface, the movable panniculus adiposus, to such a degree that we would require a narcosis to be able to make a careful electrical examination, and we have therefore made use of the jerking awny motions of small children against needle-pricks in attempting to develop a new method of examination, which is simpler, takes less time, and is also less dangerous for the child. The Examination (Figs. 176a, 176b; Figs.177a, 177b).—Let us suppose the case of a paral ysis in the peroneal muscles; the outer edge of the foot hangs down.
We now take a needle and slightly prick the child at the outer edge of the sound foot; then the child will quickly lift the edge of the foot- to escape the needle. On the affected foot the action of the peroneals will be lacking; the child can lift the toes with the anterior tibialis muscle and try to keep these out of the way of the needle, but the elevation of the outer edge of the foot which alone would fulfil this purpose is lacking.
Examination of the quadriceps: Pricking the heel with the leg hanging down causes a contraction of quadriceps as the jerking away motion. The rest of t he limb must naturally be fixed.
With this method we will he all to carry out a more exact exami nation of the single motions and we will get better information about the condition of the muscle than we would by electrical examination, as the voluntary impulse gives a finer reaction of the muscle than the electrical one. The hand placed lightly upon the belly of t he muscle or upon its tendon can feel even very slight contractions, while the other hand attempts to produce the jerking away motion by the prick of the needle.
Outline of we have carefully acquired an under standing of the spread and the intensity of the paralysis in the different muscles, we next proceed to formulate an exact plan of operation.
The first principle is to proceed as simply as possible.