Lakers are up 51-31 at the half, and it’s not because of Kobe Bryant, who was 2-for-8 for eight points in the half. It’s not because they’re going crazy from the three-point line.

It’s because they finally are taking advantage of their enormous height advantage over the Rockets.

The Rockets start no one taller than 6-9, with Yao Ming and Dikembe Mutombo out. Something the Lakers should have been punishing the Rockets for … throughout this series.

They are doing it today.

Andrew Bynum, Pau Gasol and Lamar Odom — who go 7-foot-, 7-foot and 6-10, respectively — have been conducting regular work meetings at the rim.

Between them, they are 10-for-17 in the first half, for 24 points and 19 rebounds — which nearly match the Rockets’ team totals of 31 and 19.

The trick to turning the game into a big man’s game is to keep the other guys, the little guys, from getting into the lane, and the Lakers have done that pretty well. No sightings of Aaron Brooks taking his tiny body to the rim.

Anyway, in hoops, if the talent is remotely even, the big team tends to win.

So far, that’s what is going on today.