Large-Area Injury
Some attacks affect much or most of the victim’s body -for instance, dragon’s breath, a bomb blast, a huge fire, or immersion in an acid pit. In particular, any damage described as being “area effect” or “cone,” and any external explosion, inflicts large-area injury.
A melee attack from an attacker whose Size Modifier exceeds that of his target by seven or more is also a large-area injury – if the attacker is striking unarmed or with a weapon scaled to his body size. (If he wishes to target a hit location, his tiny victim must be pinned or otherwise immobile.)
Damage Resistance protects normally against large-area injury – but if your DR varies by location, your “effective DR” is the average of your torso DR and the DR of the least protected hit location exposed to the attack (which could still be your torso), rounding up. If your DR varies against different attacks, “least protected” refers to the location with the lowest DR against that particular type of attack.
A location protected by cover or masked by the body does not count as “exposed to the attack.” Against an explosion or cone, only locations facing the blast or cone are exposed (e.g., if you’re turned away, your face and eyes aren’t exposed).
For damage caused by immersion in a hazardous environment (e.g., fire or acid), only the immersed locations are exposed.
Against a true area effect, all locations are exposed. Don’t modify large-area injury for hit location (that is, treat it as a torso hit) unless only one location is exposed. If a single limb (hand, arm, etc.) is exposed, damage in excess of that required to inflict a major wound is lost.