My only excuse for reporting the following case of myositis ossificans is that failed to follow the usual course of this long recognized condition, and also because of several interesting points in the differential diagnosis.
In 1925, Adam Gruca1 published a clinical and experimental study of this condition, with a detailed report of seventeen cases. He gives what I believe is the best classification to date. It is as follows:
1. Myositis Ossificans Traumatica:
(a) Following a severe single injury by blunt force.
(b) Following dislocations; i. e., elbow, clavicle, knee, shoulder.
(c) Development of bone along the track of perforating gunshot wounds.
(d) After clean incised wounds.
2. Myositis Ossificans Chronica:
(a) After repeated slight trauma; i. e., "rider's bone." "soldier's shoulder."
(b) Occupational.
(c) Nontraumatic; history of trauma not obtainable.
3. Myositis Ossificans of Infectious Origin.
4. Myositis Ossificans—Para-Arthritica.
5. Myositis Ossificans—Neurotica.
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