Part 18

Disarticulation of one or more toes with their metatarsal bones.

Disarticulation of one or more toes.

For any of these amputations all that is required is an ordinary boot, fitted with a cork, which is shaped to fit the stump and which fills up the space left by the amputation.

In order that the patient may walk well the scar should be dorsal and should not be tense.

We consider that the difficulty of maintaining equilibrium after removal of the head of the first metatarsal, or even of the whole of this metatarsal bone, has been much exaggerated.

Removal of a marginal metatarsal bone (either alone or with its neighbour), tends to make the foot tilt into varus or valgus; so that the boot needs to be stiffened and the sole thickened to avoid this.

CHAPTER VII

ARTIFICIAL LIMBS FOR AMPUTATION THROUGH THE FOREARM

The constituent parts of an artificial arm are the same in principle as for those of an artificial leg, they are--

1. A means of attachment preventing the appliance from dropping as the result of its weight.

2. A socket, fitted to the stump and articulated with the last named at the elbow.

3. The terminal appliance, intended to replace as far as possible the amputated hand and, if possible, resembling it in appearance. In the case of the upper limb the advantages that wood possesses in giving strength and accuracy of fit do not apply, and the arm and the forearm pieces are made of leather, with lateral steels articulated at the elbow: this joint is active in the case of amputations of the forearm but purely passive in amputations of the arm.

We will commence by describing the appliance for amputation through the forearm, taking as our type amputation in the lower half. This will furnish an example which illustrates all the principles that should guide us, the ends we should have in view, and the means by which we can attain them.

When once we have studied the apparatus by means of which the functions of the hand can as far as possible be replaced, a short description will suffice to explain what can be done when the loss of movement of the elbow and then a shorter and shorter stump in the upper arm oblige us to diminish the utility of the appliance.

We must study in turn: (1) The attachment of the upper arm socket; (2) the joint between this and the forearm socket; and (3) the appliances attached to the extremity of the forearm whether these take the shape of a hand or not.

1. POINTS OF ATTACHMENT

1. SUSPENSION.--In the exceptional amputation very low down, in which the roots of the thenar and hyperthenar eminences remain, the enlargement thus formed at the extremity of the forearm may be used for the attachment of a wristlet which may suffice to support the artificial appliance, provided that the latter is not intended for heavy work. In the latter case an attachment from the elbow at least must be added.

This method would evidently be out of the question in the usual class of case, viz. ordinary amputations through the forearm.

In these the attachment may be made in two ways:--

(1) To the humerus above the condylar enlargements, the epicondyle and the epitrochlea, the latter being much the more prominent.

(2) To the top of the shoulder, i.e. to the surface over the acromion and clavicle.

A. Attachment to the Elbow.--The simplest method of attachment is that in which pressure is exerted upon the condyles of the humerus (Fig. 124). A leather armlet laced in front is furnished with two lateral steels, curved in above the condyles and articulated at the level of the centre of rotation of the elbow joint with two similar steels in the forearm piece (the socket).

FIG. 123.--The three regions used as points of support, the shoulder, the elbow and the wrist.]

FIG. 124.--Suspension from the elbow. The side steels of the arm piece are curved in to fit upon the supra-condylar ridges of the humerus. A good method of suspension for long stumps, when the appliance is not to be used for heavy work. It should be supplemented in other cases by direct suspension from the shoulder.]

This direct method of attachment is sufficient for a low amputation, in cases where the patient does not do hard work. But if the stump is short and if the patient has to carry fairly heavy weights the appliance is only prevented from slipping by a considerable constriction of the arm, which results in a serious interference with muscular action.

B. Attachment to the Shoulder.--For this reason it is usually advisable to supplement this by an indirect attachment to the acromion and clavicle by means of a shoulder cap.

The firmest and strongest pattern consists of a piece of blocked leather, moulded to the shoulder, including the pectoral, supra-clavicular and scapular regions. This is kept in place by a strap which passes under the opposite axilla. It is cut away on the outer side of the acromion, the anterior and posterior borders being continued downwards on either side of the deltoid as two tapering straps to which the armlet is attached. In this way full liberty of movement is allowed to the shoulder (Fig. 125).

This pattern is strong, but cumbersome and heavy. It can be lightened by reducing it to an antero-posterior strap, 6 or 7 centimetres wide, over the clavicle and spine of the scapula, ending in front and behind at the level of the axillary folds in triangular enlargements. In the upper and inner angles of these are attached the ends of the axillary strap, to the lower and outer angles, prolongations from the armlet (Figs. 126 and 127).