ever see someone KNOCK or TAP on a wall to look for a STUD? sounds hollow, hollow, then THUD - this is an analogy to lung percussion - associate consolidation and pneumonia with DULLNESS, actually whenever fluid or solid tissue replaces air-containing lung tissue (pleural effusion, tumor)
Liquindi - Baka women water drumming. When you percuss a lung filled with liquid or a region of the thorax filled with fluid (eg pneumonia, consolidation, pleural effusion), how does it sound? (DULL or FLAT). compare this to hitting a drum that's filled with AIR.