Objective signs are absent, except that it is evident that the patient assumes by preference an attitude of repose, and that he keeps the involved structures as much at rest as possible. Pyrexia does not occur; the appetite and digestion are not impaired; acid sweats are not present; the urine shows no constant or characteristic alteration; there is no tendency to endo- or pericardial inflammation. If constitutional disturbance be present, it is trifling and due to prolonged local suffering and want of sleep. In by far the greater number of instances the patient remains in his usual health except the local malady.
Myalgia may affect the voluntary, and perhaps also the involuntary, muscles of any part of the body. Those most frequently involved are those subjected to continuous and excessive work, and at the same time liable to exposure to cold and damp. Single muscles or groups may be affected. The most common and important varieties are—
(1) Cephalodynia, manifested as a superficial headache, increased by movement of the scalp and attended by tenderness on pressure.
(2) Torticollis; wry neck, stiff neck—a very common form, involving the muscles of the neck, especially the sterno-cleido-mastoid. The affection is usually limited to one side, toward which the occiput is more or less firmly rotated and flexed. Great pain is experienced in attempting to turn the head in the opposite direction. The position is extremely constrained and awkward; the head cannot be moved in any direction without moving the whole body, and every effort at motion is accompanied by pain which calls forth involuntary grimaces.
(3) Omodynia, Scapulodynia, Dorsodynia—forms in which the muscles of the shoulders and upper part of the back are affected. They are very common, especially among laboring men.
(4) Pleurodynia, Myalgia of the Chest-walls.—The intercostals, pectorals, and serratus magnus may be involved. The pain is frequently referred to the region of the interdigitations of the serratus magnus with the external oblique. It is very often seated in the infra-axillary region, and is much more common on the left side. It is usually very severe, and is increased by all movements that bring the affected muscles into play. The focus of pain is sometimes a very limited spot, which is exquisitely tender upon pressure. Sometimes the pain alters its position from time to time. It is increased by deep inspiratory efforts and such acts as sneezing and coughing. Extreme flexion of the trunk from side to side also aggravates the pain. Pleurodynia sometimes comes on in consequence of severe and protracted cough, as in patients suffering with phthisis. It is then apt to affect both sides.
This form of myalgia simulates pleurisy, from which it is to be distinguished only by careful physical examination.
(5) Myalgia of the abdominal walls usually affects the recti muscles, and often assumes the guise of an acute, agonizing pain in the epigastric or pubic regions—occasionally so severe as to be mistaken for peritonitis. It is sometimes due to cough, especially in measles, but is more commonly met with in overworked and underfed tailors and cobblers as a result of the excessive action of the recti muscles in maintaining the bent posture assumed by such craftsmen at their toil.
(6) Lumbago, myalgia lumbalis.—The great muscular mass occupying the lumbar region is peculiarly prone to attacks of myalgia. Lumbago is very common in the middle and later periods of life. The attack is usually sudden and severe. Both sides are, as a rule, affected, but not to the same extent. There is constant pain across the loins, dull and aching, rarely absent altogether, always sharply aggravated by such movements as bring the affected muscles into play, and then becoming stabbing in character and almost unbearable in intensity. The spine is held stiffly, and the body is often bent slightly forward. Efforts to stand erect, to rise from the sitting posture, or to recover from the stooping position, such as is assumed in lacing one's shoes and the like, greatly aggravate the pain. In the more severe cases the patient cannot stir in his bed. There is usually tenderness upon pressure, and palpation often discovers a distinct sense of abnormal tension and resistance in the muscles.