MONTREAL — Morgan Brian turned onto her stomach and kicked the turf in pain. Red bloomed in Alexandra Popp’s blond hair like an excruciating carnation.

As happened last year at the men’s World Cup in Brazil, FIFA was confronted on Tuesday with head injuries at its signature tournament. And yet again, the response from soccer’s governing body was inadequate.

For four minutes, the Women’s World Cup semifinal between the United States and Germany was halted as Brian and Popp lay on the field at Olympic Stadium.

On a free kick by Germany in the 28th minute, both players jumped for the ball at the far post. Brian did her job expertly, heading the ball away, only to be struck from behind by Popp’s head, which landed like a punch.