for, tied in two places, and divided. The periosteum is lifted from the external surface of the bone, from the symphysis outward. Hemorrhage is arrested. The buccal mucous membrane is cut from the alveolus. A lateral incisor tooth is pulled, and the bone is sawn in the line G (Fig. 107). The bone is grasped in a lion-jaw forceps and is drawn outward. The mylo-hyoid insertion is cut; the internal pterygoid muscle is cut or the periosteum at this spot is lifted; the inferior dental artery is cut and tied; the jaw is pulled down; the insertion of the temporal muscle upon the coronoid process is cut away; and the external pterygoid muscle is divided. The capsule of the joint is opened, and the bone is separated from the ligaments which still hold it in place. Bleeding is arrested, the wound is sutured, a tube is introduced in the posterior portion of the wound and retained for twenty-four hours, and antiseptic dressings and a Gibson or a Barton bandage are applied. Partial excisions of the alveolus may be performed through the mouth by means of chisels and rongeur forceps; but if any considerable part of the body of the jaw is to be removed, an incision should be made below the jaw.

XIX. DISEASES AND INJURIES OF MUSCLES, TENDONS, AND BURSÆ.

Myalgia, or muscular rheumatism, is a painful disorder of the voluntary muscles and of the fibrous and periosteal areas where they are attached. The term "muscular rheumatism" is not strictly correct. It is possible that in some cases the muscular structure is inflamed, but it is certain that in many cases the pain is distinctly neuralgic. Muscular rheumatism may be due to cold and wet, to over-exertion and strain, to acute infectious disorders, to syphilis, to chronic intoxications (lead, mercury, and alcohol), and to disturbances of the circulation. Gouty and rheumatic persons are

especially predisposed, men being more liable to the disease than women. The disease is usually acute, but it may be chronic.

Symptoms.-Muscular rheumatism is apt to come on suddenly. The pain, which may be very acute and lancinating or may be dull and aching, is in some cases constantly present; in other cases it is awakened only by muscular contraction. The pain is frequently relieved by pressure, though there is often some soreness. The disease usually lasts for a few days, but it tends to recur. There is little, if any, fever.

Lumbago is myalgia of the muscles of the loins. Rhenmatic torticollis is myalgia of the muscles of the neck. Usually one side of the neck is attacked. The chin is turned from the affected side and the neck is stiff. Pleurodynia is myalgia of the intercostal muscles. The pain is very severe, is aggravated by deep respiration, by coughing, and by yawning, there may be tenderness, and the patient tries to limit chest-movement. In intercostal neuralgia the pain is limited, is not constant, but occurs in distinct paroxysms, and is linked with the tender spots of Valleix. Pleurodynia lacks the physical signs of pleurisy. Myalgia must not be confused with the pains of locomotor ataxia. Cephalodynia is myalgia of the muscles of the scalp. The muscles of the shoulder, upper dorsal region, abdomen, and extremities may also be attacked by myalgia.

Treatment. Remove any obvious cause. Treat any existing diathesis, such as gout or rheumatism. Rest is of the first importance. For lumbago, put the person to bed. For pleurodynia, strap the side of the chest. A hypodermatic injection of morphia and atropia into the affected muscles at once allays the pain, and a deep injection of water is often curative. The introduction of four or five aseptic needles into the muscles, and their retention for a few minutes, often acts like magic. Ironing the muscles is a good domestic

remedy. Vigorous rubbing of the area with a piece of ice allays the pain. Hot poultices do good. If the pain is widely diffused, alters its seat, or is very obstinate, order hot baths or a Turkish bath and diuretics. In chronic cases employ blisters or counter-irritation by the cautery and give iodide of potash and nux vomica. The constant electric current finds advocates. In an ordinary severe case order a hot bath, put the patient to bed with a hot poultice over the part, and order 10 grains of Dover's powder; the next day give him four times daily a capsule containing 5 grains of salol and 3 grains of phenacetin.

Myositis may be a widespread inflammation of the voluntary muscles, due to an unknown infective cause. It is a disorder accompanied by pain and stiffness, by cutaneous oedema, and by various paræsthesiæ. Myositis resembles trichinosis, and is distinguished from it only by spearing out a bit of muscle and examining it microscopically. Occasionally diffuse suppuration occurs. Ordinary myositis arises from injuries, from syphilis, or from rheumatism, and it presents the usual inflammatory symptoms. Contraction and adhesion may follow.

Treatment.-Infective myositis is treated by anodynes, stimulants, nutritious food, hot applications, and rest. If pus forms, it should be evacuated. Rheumatic myositis calls for the salicylates, the alkalies, or salol. Syphilitic myositis is treated with mercury and iodide of potassium. The remedies employed for myalgia are used in traumatic myositis.

Hypertrophy of the muscles may arise from their increased use. In pseudo-hypertrophic paralysis the bulk of the muscle is greatly augmented, but it contains less musclestructure and more fat or connective tissue. Hypertrophy of the tongue, which is due to lymphangioma, is called "macroglossia" (see p. 209).

Atrophy of the muscles arises from want of use, from

injury, from continuous pressure, from interference with the blood-supply, from disease of the nerves or their centres, or from lead-poisoning.

Degeneration of Muscles.-The muscles may undergo granular degeneration, waxy degeneration, fatty degeneration, and calcareous degeneration, and may become pigmented.

Local Ossification and Myositis Ossificans. It is not unusual for a small portion of bone to form in the bony insertion of a muscle which is subjected to frequent strain. In persons who ride many hours a day there not unusually develops the "rider's bone," which is an area of ossification in the adductor muscles of the thigh. Myositis ossificans, a widespread ossification of the muscles, is a rare disorder the cause of which is unknown, and which, if not congenital, begins at least in early life.

Tumors of the Muscles.-Primary tumors of the muscles are rare. Among those which may occur are sarcoma, fibroma, lipoma, osteoma, angeioma, myxoma, and enchondroma.

Syphilis may cause inflammation. Gummata may form, or gummatous infiltration may take place.

Trichinosis or trichiniasis is a disease due to the embryos of the trichinæ spiralis. The disease originates from eating insufficiently cooked meat which contains the trichinæ. These nematodes are thus carried into the intestine, there to develop and to multiply. In from seven to nine days a horde of embryos have developed in the intestines, and they leave the intestine by passing through the peritoneum or by means of the blood, and finally reach the connective tissue of the muscles. From the connective tissue the embryos migrate into the primitive muscle-fibres, where they dwell and enlarge. Myositis develops, and in the course of five or six weeks the parasites become encapsuled and develop

no further. The cyst-wall may calcify, and the worm may become calcified or it may live for years. Because infected meat is eaten the disease does not inevitably develop, and a few embryos lodged in muscle may cause no symptoms.

Symptoms.-The symptoms of trichinosis often appear in a day or two after eating infected meat. The symptoms of acute gastro-intestinal catarrh or of cholera morbus are common, but in some cases no gastro-intestinal manifestations usher in the disease. In from seven to fourteen days after the infected meat is eaten the migration of the parasites develops obvious symptoms. A chill may be noted; there is usually fever; muscular pain, tenderness, swelling, and stiffness are complained of. This condition may be widespread. Involvement of the muscles of mastication interferes with chewing; of the larynx, with audition and respiration; of the intercostals and diaphragm, with respiration. Skin-œdema and itching are marked. In some cases delirium exists. The writer saw in the Philadelphia Hospital one fatal case which was mistaken for erysipelas because of the high fever, the delirium, and the oedematous redness of the face and neck. Dyspnoea is frequent. Mild cases get well in a week or two; severe cases may last many weeks. The mortality varies in different epidemics from 1 to 30 per cent. (Osler). The diagnosis is made by spearing out a piece of muscle which is then examined for trichinæ under a microscope; or the worm may be detected in the feces by means of a pocketlens.

Treatment. To treat trichinosis, employ purgatives (senna and calomel) early in the case, and give glycerin, and also santonin or filix mas. When muscular invasion has taken place, sedatives, hypnotics, nourishing diet, and stimulants are indicated.

Wounds and Contusions of the Muscles.-Wounds of muscles may be either open or subcutaneous. In a longitudinal