Knockdown and Stunning

Whenever you suffer a major
wound, and whenever you are struck
in the head (skull, face, or eye) or vitals
for enough injury to cause a shock
penalty (see Shock, p. 419), you must
make an immediate HT roll to avoid
knockdown and stunning.
Modifiers: -5 for a major wound to
the face or vitals (or to the groin, on a
humanoid male); -10 for a major
wound to the skull or eye; +3 for High
Pain Threshold, or -4 for Low Pain
Threshold.
On a success, you suffer no penalty
beyond ordinary shock.