Critical Hit Table (4e Variant Rule)
From D&D Wiki
 Critical Hit Table
Use this table as stated below in place of the standard maximum damage for critical hits as laid out in 4th edition rules.
Instead of maximum damage, on critical hits, players roll 1d100 and consult this table to see the result of their hit.
Example1: On a critical the 1d100 roll produces a 33 which falls into the 31-40 category. The attack would deal normal damage +1d6 along with ongoing 1d6+2 damage of the same type as the attack. Save ends ongoing damage.
Example2: On a critical the 1d100 roll produces a 88 which falls into the 81-90 category. The attack would deal normal damage +2d6 along with causing the target to grant combat advantage until they end this effect with a save.
|Physcial Action||You land a blow on the target's leg||You land a blow on the target's arm||Your attack leaves a wound||Your attack leaves a large wound||Your attack connects with the target's head||The force of your attack knocks the target down||Your attack hits your target square in the face||Your attack hits the target's face, blurring its vision||Your attack disheartens the target's will to fight||Your attack connects hard with the target's head||Your attack is epic.|
|Effect||Slowed||Weakened||Ongoing Damage of same type as attack||Ongoing Damage of same type as attack||Dazed||Prone||Blinded||Penalty to attack rolls||Penalty to all defenses||Stunned||Target knocked unconscious for 1d4 rounds.|
|1-3||Until end of target's turn||Until end of your next turn||1d4+2 Save Ends||1d6+2 Save Ends||Until end of target's turn||Until start of your next turn||Until end of target's next turn||Until start of targets next turn||Until end of your next turn|
|4-6||Save Ends||Save Ends||1d6+2 Save Ends||2d4+2 Save Ends||Until end of your next turn||Until end of target's next turn||Until end of target's next turn||Until start of your next turn||Save Ends|
|7-9||Save Ends||Save Ends (DC 12)||1d8+2 Save Ends||1d10+2 Save Ends||Save Ends||Save Ends||Save Ends||Save Ends||Save Ends|
|10||Until end of Encounter||Until end of Encounter||1d10+2 Save Ends||2d6+2 Save Ends||Until end of Encounter||Save Ends (DC 12)||Save Ends||Save Ends (DC 12)||Until end of encounter|
- If the target already suffered from the listed effect, or if the attack power used on the critical hit roll causes the effect, the effect from the table become an aftereffect.
- Any of the effects suffered from taking a critical hit may be ended by spending a healing surge, the creature or player affected regains no hit points and must be able to legally use a healing surge