Intentional abuse of an infant is usually apparent. External injuries such as burns, bites, and bruises, as well as the skeletal changes of fractures, frequently multiple and in various stages of healing, are obviously intentionally inflicted, and are impossible accidental injuries for the nonambulatory young infant. Similar injuries in young children may be more difficult to evaluate because of their fear of and intimidation by the person who inflicted the injury. Fortunately, the high degree of suspicion regarding the nature of the injury permits the physician to make his accusations with legal protection in our judicial system. Every radiologist should be concerned with the responsibility of reporting to the referring physician the possibility of intentional trauma to infants and children. In Harris County, where Houston is located, there are 1,500 reports per month of child abuse; in other words, this approximates 18,000 cases a year in our community, and the radiologist is frequently the first physician to see evidence of the abused child. Not only is it a moral responsibility for the radiologist to report his suspicions, but in the state of Texas, as in other states, "any person having cause to believe that a child's physical and mental health, or welfare has been or may be adversely affected by abuse or neglect shall report" to the appropriate agency. A more recent amendment to this law is a penalty for failure to report. A person commits an offense if the person has cause to believe that a child's physical and mental health or welfare has been or may be adversely affected further by abuse or neglect and knowingly fails to report it. It is hoped that any radiologist recognizing either pathognomonic or suspicious signs of child abuse will have the conscience and courage to take a strong stand for the protection of the abused infant or child. Accidental injuries in older children may offer problems in diagnosis if there is no history available or if there is a denial of an injury. Some of these injuries may produce radiographic findings suggesting some form of metaphyseal or diaphyseal dysplasia. Iatrogenic injuries are frequently the result of physiologic or anatomical response to proper and lifesaving treatment. The most serious of these are found in the premature infant, who may suffer chronic lung disease or, more seriously, brain damage.(ABSTRACT TRUNCATED AT 400 WORDS)