29. Besides these signs, which characterize generally every species of luxation of the humerus, each species is marked by certain others peculiar to itself. If the displacement be downward, the arm is a little longer than in its natural state; it can be moved gently outwards; but an acute pain is the inevitable consequence of moving it forward or backward. The elbow is more or less removed from the axis of the body, by the action of the deltoid, the long portion of the biceps, and the supra-spinatus muscles, which, being unnaturally stretched, contract themselves and tend to carry the bone outward. The pains which result from this position, force the patient, in order to relieve them, to lean towards the affected side, to keep the fore-arm half-bent, the elbow resting on the hip, so that the arm, finding a place of support, may be freed from the painful movements, and from the disagreeable sensation produced by its own weight. From this attitude alone, was Desault in the habit of discovering luxations in a downward direction, and was rarely mistaken in his diagnosis. It is thus, that, in a fracture of the clavicle, the inclined position of the patient is oftentimes, at first sight, characteristic of the nature of his complaint. Beneath the hollow of the arm-pit there always exists a protuberance more or less perceptible, formed by the head of the humerus. 30. To the general signs of luxations of the humerus (28), that in an inward direction adds the following: the elbow, being separated from the trunk of the body, is carried a little backward; the humerus seems to direct itself towards the middle of the clavicle; motions backward are not very painful, while those in a forward direction are extremely so; under the pectoralis major a manifest protuberance exists; the arm is but little longer than in a natural state; the attitude is the same as in the preceding case. 31. Should a luxation in an outward direction occur, it would be particularly characterized by a hard tumour under the spine of the scapula, by the direction of the elbow forward, by its separation from the trunk, and by a little increase in the length of the arm. A protuberance behind the clavicle, an obvious shortening of the arm, together with its direction, would plainly disclose a luxation upwards.