BONES AND JOINTS.
Myositis Ossificans Traumatic. Following the severe traumatism of a wagon passing over the thorax and forearm, a male, thirty-eight years of age, found flexion and extension of the forearm limited to 6o° and 140° respectively, because of a dense infiltration oc cupying the flexor muscles of the arm. This mass was intimately attached to the humerus.
Operation.—A long incision exposed this bony tumor, and showed it to embrace the brachialis anticus. At first sight, fol lowing the removal of this in its entirety, it seemed as if the peri osteum were removed, to judge by rough bony masses ; but further chiselling eventually revealed the intact periosteum beneath. The size of this osteomatous mass was ten centimetres long, six and one-half centimetres wide.
Microscopically.—The process was too far advanced to de termine exactly the genesis ; but there are all grades of muscle degeneration, evidenced in lack of staining, cloudy swelling, fibrillation granular appearance; there is little muscular hyper plasia. The bone formation is nowhere in contact with the muscle, and it appears to originate from the connective-tissue cells converted into osteoblasts of periosteal type subsequently changed into myositis ossificans.
A second case is that of a male over whose foot a heavy wagon passed. After ten weeks' treatment a bony mass was felt to replace the tendo-Achillis, starting from the os calcis. X-ray still further verified this, and operation was done. Micro scopically, the findings were the same as above. Myositis ossifi cans of traumatic origin is omitted in all text-books. Its distin guishing feature from the myositis ossificans of progressive type lies in the nature of its isolated appearance, multiple foci being common to the former. It may be confounded with myositis syphilitics, but here concomitant data will help out.
Prognosis depends upon the connection of periosteum with bony mass or not. If the latter obtains, no recurrence need be expected.
Operation.—To guard against recurrences, the following precautions must be kept in mind: ( 1 ) Not only the bony mass, but the entire muscle is to be extirpated. At any rate, as far as the dense ramifications extend ing into the muscles.
(2) To the extent of one centimetre about the growth the healthy periosteum is to be removed.
(3) The exposed bony surface is to be freed of all osteo phytes as well as a removal of all that is pathological in compact layer of bone.
A summary of twenty-five cases on the literature is appended. —Beitritge zur klinischen Chirurgie, Band xxviii, Heft I.