Various forms of pyogenic infection are met with in muscle, most frequently in relation to pyaemia and to typhoid fever.  These may result in overgrowth of the connective-tissue framework of the muscle and degeneration of its fibres, or in suppuration and the formation of one or more abscesses in the muscle substance.  Repair may be associated with contracture.

A gonorrhoeal form of myositis is sometimes met with; it is painful, but rarely goes on to suppuration.

In the early secondary period of syphilis, the muscles may be the seat of dull, aching, nocturnal pains, especially in the neck and back. Syphilitic contracture is a condition which has been observed chiefly in the later secondary period; the biceps of the arm and the hamstrings in the thigh are the muscles more commonly affected.  The striking feature is a gradually increasing difficulty of extending the limb at the elbow or knee, and progressive flexion of the joint.  The affected muscle is larger and firmer than normal, and its electric excitability is diminished.  In tertiary syphilis, individual muscles may become the seat of interstitial myositis or of gummata, and these affections readily yield to anti-syphilitic remedies.

Tuberculous disease in muscle, while usually due to extension from adjacent tissues, is sometimes the result of a primary infection through the blood-stream.  Tuberculous nodules are found disseminated throughout the muscle; the surrounding tissues are indurated, and central caseation may take place and lead to abscess formation and sinuses.  We have observed this form of tuberculous disease in the gastrocnemius and in the psoas—­in the latter muscle apart from tuberculous disease in the vertebrae.

#Tendinitis.#—­German authors describe an inflammation of tendon as distinguished from inflammation of its sheath, and give it the name tendinitis.  It is met with most frequently in the tendo-calcaneus in gouty and rheumatic subjects who have overstrained the tendon, especially during cold and damp weather.  There is localised pain which is aggravated by walking, and the tendon is sensitive and swollen from a little above its insertion to its junction with the muscle.  Gouty nodules may form in its substance.  Constitutional measures, massage, and douching should be employed, and the tendon should be protected from strain.

#Calcification and Ossification in Muscles, Tendons, and Fasciae.#—­Myositis ossificans.—­Ossifications in muscles, tendons, fasciae, and ligaments, in those who are the subjects of arthritis deformans, are seldom recognised clinically, but are frequently met with in dissecting-rooms and museums.  Similar localised ossifications are met with in Charcot’s disease of joints, and in fractures which have repaired with exuberant callus.  The new bone may be in the form of spicules, plates, or irregular masses, which, when connected with a bone, are called false exostoses (Fig. 110).