Among 1,572 cases of children's head injuries, we have noted in 9 p. cent a secundary impairment of the neurological condition. 1) After a lucid interval, an intracranial hematoma (4 p. cent), much more after extradural than subdural, it can suddenly break out. Bradycardia and anemia are very evocative of it. 2) Without a real lucid interval (0.8 p. cent) the diagnosis of cortical contusion with oedema is settled after having eliminated an hematoma. 3) The so called baby's hemiconvulsion-hemiplegia syndrome (4.2 p. cent) is very particular in itself and its favorable evolution. In conclusion, clinical survey goes first. In emergency further investigations take place on account of the clinical findings: skull-X ray, carotid angiography and CT-Scanner.