9. In whatever manner a fracture of the os femoris may have occurred (7), its existence is characterized by the following signs: severe local pain at the instant of the accident; a sudden inability to move the limb; a preternatural mobility occurring in some particular part; a crepitation sometimes distinct, when the two fragments are rubbed against each other; and a deformity, which may be considered under the threefold relation, of length, thickness, and direction.[22] These signs, being common to most fractures, exhibit but few circumstances peculiar to those of the os femoris, except that of the deformity. Respecting this circumstance, in particular, it is essentially necessary to possess accurate ideas, because, having an incessant tendency to recur, especially in oblique fractures, it must constitute a primary object of attention during the treatment. [22] (_La longueur, l’epaisseur, et la direction._) That is, the thigh may be shorter than natural, owing to the ends of the broken bone overlapping each other; it may have a protuberance on one side, in consequence of these ends being separated or displaced laterally; or the direction of the limb may be changed, by a bend or angle being produced in the bone at the place of the fracture. TRANS. 10. It may be laid down as a general principle, that all fractures of the os femoris are accompanied with some deformity; the exceptions to this rule are too few to be worthy of notice. If this deformity be considered in relation to length, it will be found that, in oblique fractures, the limb is always shorter than that of the opposite side, a circumstance which plainly points out an overlapping of the fragments. But, on examining the place of fracture, it is easy to discover, that this overlapping arises from the inferior fragment mounting upwards on the superior one, which itself remains immoveable. Now, what power, but the contraction of the surrounding muscles, can communicate to the inferior fragment a motion from below upwards? Attached, on the one hand, to the pelvis, and on the other to this fragment, to the rotula, the tibiæ, and the fibula, these muscles have on the former their fixed, and on the latter their moveable points, and, drawing the leg, the knee, and the inferior portion of the thigh upward, they produce the displacement and shortening either mediately or immediately. In this displacement, the adductores, the semi-tendinosus, the semi-membranosus, the rectus anterior, the rectus internus, &c. are the principal agents. 11. The following case communicated to Desault by a surgeon, who had been formerly his pupil, proves how great the influence of this cause is; a cause which is indeed generally acknowledged, but not sufficiently attended to by practitioners, with a reference to permanent extension. It is this that induces me to relate the case.