 Originally , the key was narrower than it is today and had the shape of a skeleton / basic lever lock <unk> , measuring six feet ( 1 @.@ 8 m ) wide , hence " the key " , with the free throw circle as the head , and the <unk> lane as the body . Due to the <unk> of the key , imposing centers , such as George <unk> , dominated the paint , scoring at will . To counter this , the key was widened into 12 feet ( 3 @.@ 7 m ) from 6 feet ( 1 @.@ 8 m ) at the onset of the 1951 – 52 NBA season . 
