Strike Out or Foul Ball

Question
High School batter has a two strike count. At the next pitch she swings and makes contact with the ball with her wrist instead of the ball. The ball goes into the air and drops to the ground behind the home umpire. Home umpire declares a strike out with the explanation that the ball did not strike the bat. I attempted to question the call, but with the threat of being thrown out, I didn't pursue.

I do not understand the call. I thought hand/wrist was considered part of the bat, therefore, foul ball.

Answer
Coach, one of the biggest myths in the game, "the hands are part of the bat".  The hands are part of the player!

If the ball hits the batter, even the hands, you have a dead ball.  If the batter is hit by the pitch while swinging, you also have a strike.

The umpire made the correct call.