The roentgen examination can be very helpful in making the early diagnosis of osteomyelitis. Within the first 3 days after the onset of symptoms, soft tissue changes are visible roentgenographically. A local deep soft tissue swelling adjacent to the metaphysis of a growing bone without superficial edema should alert the radiologist to the possibility of osteomyelitis. The diagnosis is almost certain if there is also local tenderness clinically. Several days after the onset of symptoms, swelling of the deep muscles and obliteration of the lucent planes between the muscles are visible roentgenographically, even though the enlargement of the deep muscles may not be appreciated clinically. In order to appreciate the soft tissue changes that occur early in osteomyelitis it is most important that the normal as well as the abnormal side be examined roentgenographically.