The sketch is from Dr. Baden's autopsy via the New York Times article.
Since all the wounds were to the front of the victim, the stories about Brown shot while running away appear to be false. Baden found no evidence of powder residue on Brown's body, but he did not have access to Brown's clothing, so that point is still unclear.
If Brown was in contact with Wilson and struggling for the gun, as the police narrative would have it, there should be "powder burns" around the wounds. Brown was wearing a short-sleeve shirt, and the forearm wound would have been on exposed flesh as would the wound to the top of the head and right eye.
This pattern would be consistent with a left-handed shooter jerking the trigger, understandable under stress. Also, it looks like the pattern a right-handed shooter would get when overly anticipating recoil. This is especially the case if the officer is shooting a .40 S&W and is a little recoil or muzzle-blast shy.
However, this is assuming the shooter and the target are standing face to face and relatively square to one another. If that were the case, I would guess the distance from Officer Wilson to Michael Brown would have been beyond arms' length.
It's conceivable that Brown was standing at an angle toward the officer -- say, after he had shoved Wilson back toward his cruiser with an extended right arm -- sort of the way he had just man-handled the store owner.
The bullet that struck Brown's right eye exited out the chin and re-entered around the collarbone. We do not know Officer Wilson's height but we do know that Brown was around 6'4", according to recent reports. Assuming Wilson to be in the normal range for a police officer, that's a little hard to figure. One would think Brown's head would have had to have been lower than the officer's shoulders.
Is it possible to explain it as being a result of Brown's head being lowered? Yes, it is. Keep in mind that all elements involved are moving and moveable. Imagine that Brown, struck in the arm, looked down just as the officer fired the round. (We're assuming a sequence here that is likely but not certain by any means.) It struck Brown's eye, the impact of the bullet and the reaction to being struck would move Brown's head back and up so that in that hundredth of a second, the bullet comes out the bottom of the jaw and goes down instead of back.
The big problem for the police -- unless they can establish that all the shots were fired while Brown was on top of Wilson in the squad car, and, again, you should have stippling from hot powder on Brown's skin -- is the shot that went into the top of Brown's head. Having his head down in a tackle-like charge doesn't really explain it. The bullet stayed in the body. There's no exit wound at the base of the skull. If Darren Wilson is 6'4" or over then I can accept that he fired as Brown put his head down to charge. If not, it seems much more likely that he fired the fatal round after Brown was on his knees.
In fact, it seems most likely that Brown, struck repeatedly in the arm, dropped to surrender. This does not indict Wilson. If he was reacting to a perceived threat, he may have fired the last two shots before he could process the realization that Brown had surrendered. After that many rounds, the officer was half deaf and would have had difficulty hearing anything Brown said.
Again, eyewitnesses on either side, including, frankly, the officer himself are not to be accepted as unquestionable. Too much is happening too fast.
Let me give one purely speculative scenario for all the data I've seen so far. First, Wilson addresses the two young men in the street. They, having just stolen cigars, assume that the contact is related to that. Wilson attempts to get out of the car. Brown strikes him/shoves him back. Wilson attempts to draw his weapon. There is perhaps a struggle, and Wilson is struck again. He gets a round off, frightening Brown who starts to run. Wilson gets to his feet and fires again. Brown, realizing he can't outrun a bullet, turns and either decides to give up or to attempt to rush the officer. Wilson is still shooting as Brown turns into the rounds that strike his right arm. Brown then drops and tries to give up, but Wilson, panicked and confused by pain fires the two fatal rounds