Truss, a contrivance for preventing the reappearance of a hernial tumor after its reduction. The general form of the truss is a flat steel spring covered with soft leather or oiled silk, and having its ends approximating to within a few inches of each other; attached to one end is a small round or oval pad, stuffed with cotton or wool, and having for its basis a small iron plate; the other end of the spring has either a larger and flat pad, or a strap connected with it. The smaller pad is placed over the ring or point where the hernial tumor has protruded (see Hernia), and the string passes over the hip, and either exerts its pressure by means of the large counter pad on the back, or is by means of a strap passing over the opposite hip connected with the pad by a buckle or eyelet and button on the back of the pad. Sometimes, where it is necessary to adjust it with great care, another strap passing over the inner surface of the thigh connects with the spring on the back. Where, as is sometimes the case, there is a double hernia, this spring is made sufficiently long to clasp over both hips, and has a pad at each end. In this case there should be a pad attached to the middle of the spring to exert gentle pressure on the spine, and thus keep the truss more perfectly in position.

There are numerous patterns of trusses, varying considerably in form, but they may all be reduced to three classes: those with a flat pad, intended to press upon the whole surface of the ring or place through which the intestine protrudes; the oval or egg-shaped pad, which presses directly into the ring, and thus prevents the escape of the intestine; and the semicircular pad, which acts by supporting the intestine from above and pressing it away from the point of rupture. The truss, though preventing the recurrence of the hernial tumor when properly adjusted, seldom effects a radical cure. This has been attempted by pur-posely so adjusting it as to cause it to produce some inflammation and adhesion of the serous surface around the ring so as to effect complete occlusion of it; but it should never be done except under the direction of a skilful physician, as it is attended with danger.