This disease is an inflammation of the external covering of bone (periosteum) and is usually produced by wounds, pressure, or crush ing the part. The periosteum is well supplied with sensitive nerve endings and when inflamed is very sensitive to pressure and may cause lameness. This condition is often difficult to determine, and even an acute observer may fail to locate the point of its existence. There are three forms of periostitis—aseptic, purulent, and fibrous.
Aseptic periostitis when it becomes chronic causes such a bony enlargement (exostosis) as is seen in the callous formation following the fracture of a bone. The formation of such a tumor or enlargement on the surface of a bone is liable to occur in any part of the bone covered with periosteum, and when found near a joint involving two or more bones it is liable to result in their union (anchylosis).
Treatment.—Applications of cold water to check the inflammatory processes is indicated for the first few days in aseptic periostitis, followed by hot fomentations to hurry resorption of fluids. Massage should then be given with camphor ointment, mercurial ointment, soap liniment, or Lugol's solution. In the chronic form point firing or a biniodid-of-mercury blister will be found beneficial.
Purulent periostitis follows wounds which reach the periosteum and become infected, as observed in compound fractures, or it may result from advancing purulent conditions in neighboring structures, as in foul foot. It may also occur in the course of an infectious disease, when small abscesses are formed under the periosteum (subperiosteal abscess). It may lead to necrosis of the bone or a fistulous tract from the bone to the surface. There is usually much pain and fever, and the odor from the wound is offensive.
Treatment.—In this form of periostitis the periosteum should be freely incised, followed either by continuous irrigation or frequent injection of the wound with antiseptic solutions.
Fibrous periostitis.—This form of the disease consists in the thickening of the outer layer of the periosteum from the inflammation reaching it from neighboring structures. This newly formed fibrous tissue may become ossified or may transmit the inflammation to the deeper bony structures. It is frequently seen in cases in which there has been an intense inflammation of the skin close to an underlying bone.
Treatment.—The treatment should be the same as that recommended for aseptic periostitis.
OSTEOMYELITIS.
This term refers to an inflammation of the bone marrow, which is most commonly seen following the bacterial infection of a compound fracture and usually results in pus formation. The bone is melted away and pus escapes from the bone under the periosteum, involving the soft tissues. It is principally confined to the long bones and seldom affects more than one.