How many "Rule of __" is there in forensic and medicine?

NEET PG
#1

How many “Rule of __” is there in forensic and medicine?

Such as Rule of 9 in Burns
Other plz

Rule of 12 for Rigor Mortis

What’s Rule of 12 ?

12 hours to set in
12 hours to stay
12 hours mein Khallas

Thanks