Primary traumatic benign midbrain haematoma in hyperextension injuries of the head.

Primary traumatic brain stem injury occuring in isolation is not universally recognized as a distinct pathological entity which may follow a head injury. We describe two patients with clinical and radiological evidence of primary posttraumatic midbrain haemorrhage occuring in isolation associated with good recoveries. It is suggested that paramedian midbrain syndromes associated with midbrain haemorrhages should be recognized as a distinct, although unusual, complication of hyperextension injury to the head which may have a benign course.