At the extremity of an artificial arm, whether it be an arm of natural shape or a worker's arm simplified to the form of a jointed rod, any of the appliances already described for forearm amputations can be screwed on as required.
It is by the use of these appliances that Gripouilleau's old ploughman's arm, which ended in an interchangeable hook and ring, has been improved.
Apart from their actual economic value, results have been obtained by use of these terminal appliances, in many different skilled trades, which are of the greatest possible interest.
For reasons that we have indicated in describing the attachment of the elbow, the various attempts that have been made to give to the wrist a mobility that is under control have not so far led to the invention of an appliance that is both strong and durable. For this reason we consider that until something new is designed it is better to make the terminal appliance a fixed one.
CHAPTER IX
ARTIFICIAL LIMBS FOR DISARTICULATION THROUGH THE SHOULDER JOINT AND AMPUTATION THROUGH THE DELTOID MUSCLE
So far as function is concerned these operations are identical; a short arm stump is incapable of transmitting movements to the socket of the artificial limb.
That is to say, our appliance will be a purely passive one, and at the present time it is useless to attempt to make any sort of worker's arm. We must aim simply at supplying a limb which imitates the external shape of the arm, with an elbow joint which can be locked with a ratchet. At most it is possible by a movement of the opposite shoulder to work an automatic thumb by means of a cord, as a rule, however, a simple spring thumb is preferred.