We report two patients in whom bullets in the brain migrated into the adjacent lateral ventricle and moved freely as a consequence of gravity. A review of the literature suggests that the spontaneous migration of intracerebral bullets is influenced by cerebral softening, the specific gravity of the bullet compared with brain tissue, and the sink function of the cerebral ventricles. In patients undergoing the surgical removal of intracerebral or intraventricular bullets, it is recommended that an x-ray be obtained after the final positioning of the head.
