Emphysema consists in the air of the lungs is suing into the bag of the pleura, and generally from thence into the cellular tissue in the vicinity of the fracture, and ultimately over the whole in teguments of the thorax, and even the whole body. If the air which is inspired by the lungs, and from them issues into the pleuritic bag, does not escape at the wound of the pleura into the subcutaneous cellular tissue, it makes the lungs of the affected side collapse, and by accumulating in the one hag of the pleura, presses on the inediastinum and diaphragm; and this so impairs the functions of the other half of the lungs and the smaller circula tion, as soon to prove fatal. The escape of the air, therefore, from the pleuritic pouch into the cutaneous cellular tissue is favourable. Blood is often extravasated, as well as air, in the pleuritic bag, and the lungs become inflamed. The treat ment consists in making punctures with a lancet in the region of the fracture, or wherever the air is diffused, and if oppression of breathing continues, paracentesis thoracis should be performed, and a cupping glass with its syringe applied to the wound. Emphysema results also from the wound of a sword, or any other sharp pointed instrument, from the bursting of a vomica, from violent respi ration during parturition, from foreign bodies in the larynx and trachea, from blows on these organs, and even on the back of the neck; from violence in the reduction of a dislocated shoulder joint; from a suppurated lymphatic gland in the region of the neck, and as a sequela of pneumonia and typhus fever. The ribs sometimes become carious after fracture, and require to be removed.
Luxation or Dislocation (from luxo or disloc^, to put out of place,) is the displacement or those bones which form a joint, and may occur either spon taneously or in consequence of external violence. When dislocation occurs spontaneously, it arises from relaxation of the ligaments and muscles; from palsy; from matter accumulated in the joints af fected with white swelling or morbus coxarius. The other species of luxation, and much the more common, results either from violent motions or ex ternal injury, and is divided into simple, compound, primary, consecutive, complete, incomplete, and subluxation.
The shoulder joint is dislocated in four direc tions; the head of the os brachii may be forced either directly downwards into the axilla, inwards on the venter of the scapula, backwards on the dorsum of the scapula, or upwards on the coracoid process of the bone. The first of these is much the most frequent, and is probably the most com mon luxation that occurs; it is characterized by a conspicuous depression beneath the acromion, in place of the round swell of the shoulder, by the patient inclining his body to the arm, in order to relax the muscles, nerves, and blood-vessels, and relieve the pain, by his supporting the arm with his other hand or on his knee, and not being able to bring it close to his side, or lift it to his head.
The capsular ligament and short muscles around the joint are more or less lacerated, while the pec toralis major, the deltoid, latissimus dorsi, teres major, and biceps are thrown into violent action, and contribute to produce the displacement by their sudden contractile efforts, which are perform ed to prevent the displacement of the bones. The head of the os brachii is forced out of the glenoid cavity between the long head of the triceps and the subscapularis, and rests on the inferior costa of the scapula. This is an example of simple, primary, as well as complete luxation. The arm is a little longer, but the difference is scarcely perceptible; the head of the os brachii is sometimes felt in the axilla, when the arm is removed from the side; paralysis occasionally occurs from pressure on 'the nerves, and crepitus from gurgling of the synovial fluid, which latter phenomenon is exceedingly lia ble to deceive the surgeon. Various modes of re duction have been recommended both by the an cients and the moderns; but the most simple and sure method is to fix the patient firmly and properly, as represented in Fig. 10, of Plate DXVII. so that the scapula is made the resisting point, which may be accomplished with a sheet or an apparatus having a hole to admit the arm to pass through, to which is to be affixed a rope extending to a beam of wood or kitchen poker laid across the outside of the door or window of the room, a Nrct towel is then to be applied to the affected arm above the el bow-joint, and over this, a hank of worsted in the form of the double clove-hitch, to the nooses of which the one end of the pulley apparatus is to be affixed, while the other end is fastened to a piece of wood placed across a door or window opposite the other. When every thing is thus properly ad justed, the patient is to be bled to fainting, and supported in a chair by an assistant, while another instantly begins extension, and continues it gradu ally and slowly until the surgeon, by poising the head of the os brachii with a towel folded like a bandage or compress, raises it opposite the glenoid cavity of the scapula into which it starts with a pe culiar sound; the assistant then suddenly loosens the pulley apparatus and removes it. The operator next puts a cushion in the axilla, bends the fore arm across the chest, binds it there to the side, and gives support to the elbow with a long roller, as illustrated in Fig. 9 of Plate DXVII. In gene ral, tartrate of antimony in small doses should be given before using the lancet, as a great quantity of blood is often required to be taken in order to pro duce fainting.