1 . PRELIMINARY QUESTIONS - JURISDICTION OF THE COURT - LIMITS - JURISDICTION OF NATIONAL COURT - ASSESSMENT OF THE RELEVANCE OF THE QUESTIONS RAISED AND THE NECESSITY FOR A PRELIMINARY RULING ( EEC TREATY , ART . 177 ) 2 . SOCIAL SECURITY FOR MIGRANT WORKERS - COMMUNITY RULES - PURPOSE - INVALIDITY INSURANCE - DECISION OF A NATIONAL INSTITUTION CONCERNING THE DEGREE OF INVALIDITY OF A WORKER - CONCEPT - DECISION RECOGNIZING INVALIDITY - INCLUSION - LATER DECISION ESTABLISHING THAT THERE IS NO INVALIDITY - EXCLUSION ( EEC TREATY , ARTS 48 AND 51 ; REGULATION NO 1408/71 OF THE COUNCIL , ART . 40 ( 4 ) AND REGULATION NO 574/72 OF THE COUNCIL )