Part 21

As to the attempt which Beaufort appears to have made to give movement to the wrist also, we do not believe that any practical result has as yet been attained.

For the relative length of the fingers and the utility of a nail on the thumb and on the index finger see figures 150 and 151.

Shape of the Hand.

In the usual pattern (Figs. 149 and 151) the fingers are semiflexed and the thumb grips against the index finger, which is shorter than the middle finger as in the natural hand. If it is desired to pick up a ball, for example (Fig. 151), it will be seen that the middle finger projects and gets in the way. For this reason it is advisable that the index finger be longer than the middle, and in addition it is useful to furnish the thumb and index finger with a little projection representing the nail (Fig. 150).

In figure 148 will be seen an arrangement which allows the thumb to grip not by the tip, but by the whole length of its palmar surface (to hold, for example, a notebook). The fingers of this hand have ball and socket joints constructed in the way shown in figures 152 to 154. The joints keep passively the position in which they are placed. The attachment of the ball of the joint on an intermediate tenon is similar to that of the thumb shown on page 98. The articulation of the index finger prevents the sufficient excavation of the thenar eminence for the insertion of the Beaufort thumb with its powerful spring. The wrist rotates upon a bayonet joint.

The fingers shown in figures 155 to 157 are joined together into a single piece, which articulates with the metacarpal part of the hand upon a transverse axis.

They are held in a position of flexion at the metacarpo-phalangeal joints by four palmar springs and they are opened away from the thumb by the action of a cord which bifurcates from the thumb cord on the back of the hand. The pull of this cord is exerted upon the upper angle of a triangle from the lower border of which four cords pass on to the back of the phalanges. Figure 156 shows detail of a finger. We know that attempts have been made to isolate by surgical means the masses of the extensor and flexor muscles in the end of the stump, making from them little prominences, perforated with a tunnel which is lined with skin. The cords pass through the tunnels, and in this way are worked voluntarily. We are not sure that this is practicable.

In figure 155 are seen the cavity in which the finger portion works and the axis upon which movement takes place, also the four palmar springs. In figure 157 the arrangement of the cords. In figure 158 the attachment of the spring to the finger. This pattern, which we have designed and which is not patented, seems to us to be simpler than those in which the interphalangeal joints are also articulated and are automatic. It gives a more accurate grip between the tips of the thumb and index finger.]

The Brunet Grip.--The Brunet grip is described here because of its resemblance to the automatic thumb, both being worked on the same principles.

Below the leather forearm piece, which laces up, the lateral steels are continuous with each other in the form of an arch, to which the grip is riveted.

The latter consists of a strong semicircular piece of metal facing downwards, ending in a pair of wide and thick jaws, like those of a locksmith's pliers. When the apparatus is at rest, these are kept in contact by the pressure of two powerful fixed springs, attached to the semicircle on the forearm above and to the jaws below. The external and dorsal spring is attached to the tip of its jaw, the internal and palmar (the side on which the manipulating cord is attached) to the base of it.

The pliers are opened in the following way:--

Inside the semicircle to which the jaws are attached, lies a cylinder with its ends cut obliquely; this rotates about a transverse axis, and when at rest lies with its longer side upward. To the palmar edge of the shorter side is attached a transverse eccentric, to which is hooked a cord actuated as described in figure 146. When this is drawn upward the cylinder rotates so that the wider side comes between the jaws of the pliers and opens them; when the cord is relaxed the springs turn the cylinder back again find the jaws close. Figures 158 and 159 show the appliance at rest and with the jaws open.

This appliance is patented and is made in one piece. We demonstrate in figure 160 that it would be very easy to make the pliers detachable from the forearm, with a screw connection, just as is done in the various other appliances which will be described.]

The grip of the automatic thumb always lacks power, for two reasons. There is no room in the thenar eminence to fit a powerful spring and the grip has always a very narrow hold.

The Brunet grip is an actual pair of pliers, shaped like these and furnished with a powerful spring. It is opened by a cord like that of the automatic thumb. Figures 158 to 160 explain the mechanism. It is an excellent appliance with which the wearer can carry out the majority of the actions of everyday life. It has, however, the disadvantage that it is not shaped like a hand--a point to which patients attach much importance--and, moreover, it is a part of a patented appliance, for which an interchangeable hand is not manufactured. So that in order to have in addition an artificial hand, which is capable of being removed and replaced by one or more of the appliances which will be described later, it would be necessary for the patient to possess two complete artificial limbs, and changing from one to the other would evidently be inconvenient.

We generally prescribe this appliance for patients who have lost both arms, for one side and as a supplementary appliance.

There are other similar models into details of which it is unnecessary to enter. Those in which the grip is opened by movements of pronation and supination are obviously only suitable for certain rare cases (very long stumps, with free movement).

B.--APPLIANCES FOR USE IN PLACE OF THE HAND.

The general principle is to fit to the end of the forearm piece an attachment which can be screwed on or unscrewed at will and which carries an appliance which is adapted to the various more or less specialised movements of the patient's trade.

Naturally the results thus attained must always be imperfect; but however little perseverance and ingenuity he may possess, the patient finds that he is able to educate the remaining arm, even when it is the left, to replace the amputated one in a way that is often remarkable. It is to this education that attention must be specially directed in the workshops for the re-education of the maimed.

1. Knife and Fork.--The first necessity is to be able to eat, and by certain very simple devices a fork, spoon or knife may be fixed to a wooden hand, whether the thumb be mobile or not.

As a general rule if the patient has one arm intact, he uses the sound hand only for this purpose, but when both forearms have been lost an appliance is indispensable.

We have already described how in the hand with an automatic thumb, room can be left between the index and middle fingers for the handle of a spoon or fork. A direct grip can also be obtained with the hand shown in figure 147.

The hand with five automatic digits (p. 105) is usually arranged in such a way that it is possible to hold a tumbler for drinking; but a patient with an amputation of one hand drinks with the other, and one who has lost both hands can drink with a straw.

These appliances have replaced that in which the knife or fork is attached to a block of wood which can be fitted into the palm of the hand when required. It is inconvenient to be obliged to carry these special implements about.

Raynal's fork-rest has the advantage over the last mentioned that it fits any fork. Figure 161 shows very clearly its construction and the way in which it is used. The small special attachment, which is screwed in place, is not cumbersome and can quite well be carried in the pocket; it is, however, even more convenient to have an appliance which is capable of gripping the fork directly like those described previously.

2. Appliances for Workmen.--All the appliances that are attached to the arms in place of the artificial hand for performing various kinds of work are elaborated from two simple forms: the hook and the ring (for catching hold and carrying a parcel, for holding a handle, etc.). A glance at figure 162 will show the nature of these and the way in which they are used. But it will also be understood that if the simple ring and hook are useful for equally simple purposes they are altogether insufficient for skilled labourers whose work entails a certain special adroitness, e.g. joiners, locksmiths, agricultural labourers, etc.