A surgical handbook : for the use of students, practitioners, house-surgeons, and dressers / by Francis M. Caird and Charles W. Cathcart.

  • Caird, Francis Mitchell, 1853-1926
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: A surgical handbook : for the use of students, practitioners, house-surgeons, and dressers / by Francis M. Caird and Charles W. Cathcart. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

    248/290 (page 236)
    |)ractically that empirically advocated by Count Beaufort in his cheap limbs for (lie working classes. The effect of this close imitation of nature explains why it is that, in amputations below the knee, the gait of the patient witli a lieaufort limb is so good, equal to, if not l)etter than, that attained by a patient with the most exjjensive liml) ever made. While this forni of curved sole gives such good results and is so simple, two secondary objections may be raised against it:—(i) That it is awkward in appearance. (2) Thai it does not yield laterally so as to accommodate itself to a side slope. To obviate the first oljjection, when desired a spring might be arranged so as to flatten down the fore part of the foot when not actually ]iressed. upon, and the second may be met by allowing n slight lateral play in tlie foot controlled by strong springs. These objects are not necessary, however, and besides increasing expense might introduce a source of weakness into the limb. Whatever else instrument-malvers may do to obtain an ap]iearance, they should en-^ure that the trajectory of the knee is in a straight line as the fool rolls forward. However, an artificial foot which pivots at the ankle, or on the balls of the artificial toes, must make the knee pass through the arc of a circle, an<l not continue in the desired straight line. A slight amount of lateral play in the foot may be per- mitted if desired. When a stump ends shortly aliqve (he level of any joint, the new joint may be in the form of a transverse rod working in a socket (hinge joint). When the stump comes below the level of the new joint, the axis must be made to work on two* rule joints, one on either side of the stum]). This form of joint is said to be less lasting than the other, but is very often unavoidaljle. (f.) Artificial Knee.—According to circumstances, a rule or a hinge-joint may be emjiloyed ; but, to avoid friction, the bearing must always be taken on tlae upper of the two pieces forming the joint (see \\ 235). When the artificial limb is straightened, the line of downward strain should pass in front of the axis of the knee-joint, which should then be locked so that it cannot over- extend. This imitation of nature permits the patient to bear full weight on the straight knee without any fear of its giving way. The knee will bend easily enough as the thigh flexes to lift the leg off the ground, and the swing forward will again straighten the knee for the next step. In .some cases a slight straightening spring is needed. By the artificial tendo Achillis mechanism with appropriate springs, the artificial knee- and ankle-joints are always extended and always flexed together. The latter combination is useful in clearing the ground as the leg is carried forwards for a fresh step, but the double extension makes the lower limb, when supporting, pivot forwards <in the fore part of the foot, and this, as we have already seen, is a <lisadvantage to the gait. For cheap limbs, the knee is kept rigid while the patient walks : but in most it is made to bend by the relaxation of a spring for convenience when the patient sits down. * Like the joint of a foot-rule.