4. This accident is characterized, 1st, By a severe pain experienced by the patient, at the place of the fracture. This pain is increased by the elevation of the arm, which, generally hangs motionless down along the side. 2dly, If the humerus be removed from the trunk, the hand being at the same time placed on the acromion, the extremity of this apophysis is felt sinking downward, creating thereby an evident depression in the part. 3dly, Generally, the two fragments lose, of their own accord, their relative position; and unless the precaution about to be mentioned be used, their displacement becomes manifest, being produced by the weight of the arm, and the contractions of the deltoid muscle. 4thly, The head is inclined to the affected side. § II. OF THE REDUCTION. 5. Two different processes have been long in use for the reduction of fractures of the acromion. One consists in elevating the arm almost to a right angle with the body, in order, as Heister remarks, to throw the deltoid muscle into a state of relaxation, and then to be able, with the fingers, to place the fragments in their natural situation. In the other mode, the humerus is suffered to retain the position it has assumed, that is, to hang down the side; the surgeon then taking hold of the elbow, pushes it vertically from below upwards, in such a manner, that the head of the bone, pressing against the acromion, elevates and replaces it. 6. Petit seems to have adopted indiscriminately these two methods, one of which, however, is greatly superior to the other. Indeed, it is evident, that if the humerus be removed from the trunk, its head will necessarily sink down in the glenoid cavity. Being thus separated from the fractured apophysis, it leaves beneath it a hollow or vacancy, into which the fragment will be pushed, should it be in any measure, compressed by the casts of the roller, during the application of the bandage. 7. On the other hand, if the arm still fixed against the side, be pushed upwards, it will afford to the acromion a solid point of support, which, during the application of the apparatus, will prevent its displacement downwards. This consideration is unquestionably of moment, during the process of reduction; but ought more particularly, to command the attention of the practitioner, in the choice of means destined to maintain the reduction. § III. OF THE MEANS FOR MAINTAINING THE REDUCTION.