Combat Maneuvers against Prone opponents

[Pugbear]

How do you handle Combat Maneuvers against someone who is prone? Someone who is prone gets a -4 to AC against melee attacks, and a Combat Maneuver is considered a melee attack but AC is not part of the CMD.

So, what do you do if say, your attempting to Disarm, or Grapple someone who is prone? Would you simply take the -4 off his total CMD, or perhaps add +4 to the CMB of the person attempting the maneuver against the prone victim?

Am i missing something in the rules that explains this situation

[Quandary]

Pugbear wrote:

Am i missing something in the rules that explains this situation

...Yes.

PRD:Combat Maneuvers, CMD wrote:

A creature can also add any circumstance, deflection, dodge, insight, morale, profane, and sacred bonuses to AC to its CMD. Any penalties to a creature's AC also apply to its CMD. A flat-footed creature does not add its Dexterity bonus to its CMD.

It's easiest to look at it this way:

They've explained it in basically the longest, most round-about way, but CMB vs. CMD can basically be treated as a normal melee attack roll vs. Touch AC, just with different modifiers applied to each (different Size Mod, +BAB and STR to CMD). There IS a few discrepancies, like untyped and Luck AC bonuses which apply to Touch AC but not to CMD according to RAW, but I'm willing to bet those were overlooked and will be added in the next Errata/Update that is supposedly being released soon. (many 3.5 maneuvers used Touch AC for part of their resolution, and this is why Touch AC makes sense as a 'component' of CMD - if you don't include them, then 0 BAB/ 0 STR mod characters with these Touch AC bonuses are harder to touch than to grapple, which makes no sense)

The only other difference I can see is regarding the stunned condition:

PRD: Combat Maneuvers wrote:

If your target is stunned, you receive a +4 bonus on your attack roll to perform a combat maneuver against it.

PRD: Glossary wrote:

Stunned: A stunned creature drops everything held, can't take actions, takes a –2 penalty to AC, and loses its Dexterity bonus to AC (if any).

Now why that wasn't just included as a -6 (or -4?) penalty to CMD under the Stunned condition is beyond me, but hey, I didn't write the rules.

[Pugbear]

Hey thanks! The book wasn't with me at the moment and i simply looked up the prone condition in the PFsrd and didn't see the bit about any penalties to AC also effecting the CMD.