When a player says "How does the orc's arm break and cut his jugular?" the game master needs to be able to say "As your mace came down from above, the orc put an arm up to shield himself from your weapon's full weight. Your mace snapped the orc's arm so hard that the fracture broke the skin. The force of the blow carried that jagged bone into his exposed throat, cutting his jugular." Players love that stuff.