▁K ern oh an ' s ▁not ch ▁sometimes ▁cause ▁confusion ▁and ▁result ▁in ▁mis di agn osis . ▁Such ▁a ▁case ▁is ▁described ▁in ▁an ▁account ▁by ▁Wolf ▁at ▁the ▁University ▁Hospital ▁in ▁G ron ingen , ▁Netherlands : ▁" A ▁ 3 9 ▁year - old ▁man ▁sust ained ▁a ▁minor ▁head ▁injury ▁when ▁he ▁was ▁struck ▁on ▁the ▁head ▁by ▁a ▁golf ▁club . ▁ 5 ▁hours ▁later , ▁he ▁had ▁sudden ▁on set ▁of ▁head ache ▁with ▁n ause a ▁and ▁vom iting , ▁Sim ult ane ously ▁he ▁developed ▁mus cle ▁weak ness ▁on ▁his ▁left ▁side . ▁He ▁then ▁became ▁som n ol ent . ▁A ▁CT ▁scan ▁showed ▁a ▁sub d ural ▁blood ▁collection ▁on ▁the ▁left ▁side ... th ese ▁find ings ▁puzz led ▁the ▁att ending ▁ne uro log ist ▁as ▁well ▁as ▁the ▁radi ologist ▁who ▁both ▁expected ▁the ▁ab normal ities ▁to ▁be ▁on ▁the ▁opposite ▁( right ) ▁side . ▁The ▁radi ological ▁techn ician ▁remarked ▁that ▁the ▁left - right ▁marks ▁were ▁not ▁in ▁the ▁usual ▁place ▁on ▁the ▁monitor ▁screen ▁and ▁argued ▁that ▁the ▁latest ▁scan ▁had ▁been ▁a ▁cor onal ▁inf und ib ul um ▁scan ▁in ▁which ▁a ▁top - view ▁is ▁used ▁instead ▁of ▁a ▁bottom ▁view ... It ▁was ▁then ▁decided ▁that ▁the ▁patient ▁had ▁a ▁right - s ided ▁ac ute ▁sub d ural ▁ha emat oma . ▁In ▁the ▁operating ▁room ▁a ▁right - s ided ▁dr illing ▁hole ▁was ▁made ▁but ▁no