1. The fore-arm, composed of two bones, neither of them very strong, and covered below by a small quantity of soft parts, is exposed still more than the humerus, to the action of external bodies, and is articulated at the upper end in such a manner, as not to yield, like it, in every direction to the impulses which it receives. From these considerations, it is one of those parts where fractures most frequently occur, and, in a comparative view of affections of this kind in the Hotel-Dieu, it has oftentimes held the first place. 2. It would be useless to mention here the disposition of the bones which compose the fore-arm, their irregularly prismatical form, their thickness unequally distributed, their direction obviously different, and their motions differently combined. It is sufficient to observe, that, for the perfection of one part of these motions, a space, wide in the middle, and narrow at the ends, must separate the two bones, that, without this space the radius, impeded in its movements on the cubitus, would compress the muscles, restrain their action, and would be unable to perform the motions of pronation and supination; whence the fore-arm, being confined, as it were, to mere flexion and extension, would not, in its uses, correspond to our wants. These things being premised, we will observe, that fractures of the fore-arm may have their seat, 1st, in both bones at the same time; 2dly, they may occupy but one of them: hence three kinds of fractures more or less different in their phenomena, their consequences, and their treatment. FRACTURE OF THE FORE-ARM. § II. OF THE VARIETIES AND THE CAUSES. 3. Fractures of both bones of the fore-arm, may occur either at the ends, or in the middle of the limb. Frequent in the middle, and somewhat common below, they seldom occur in its upper part, where the fleshy portions of numerous muscles, combined with a considerable thickness of the ulna, resist the motions which tend to produce them. The two bones, though most commonly broken on the same line, are, however, sometimes broken on different ones. The fracture is almost always single: at times, however, it is double, and Desault, in particular, was once called to a patient, over whose fore-arm the wheels of a carriage had passed, and had broken it both in the middle and at the lower end, so that it evidently exhibited six fragments distinct from each other. The two middle ones, though completely insulated, united again to the others with but very little deformity. Like all other similar affections, these may be rendered compound by wounds, splinters, &c. circumstances which, as they fall within the general class of such injuries, will not be treated of at present.