In rugby union a scrum is a means of restarting play after a minor infringement. It involves up to eight players from each team, known as the pack or forward pack, binding together in three rows and interlocking with the free opposing teams forwards. At this point the ball is fed into the gap between the two forward packs and they both compete for the ball to win possession. Teams can be penalised for intentionally causing the scrum to collapse, and for not putting the ball into the scrum correctly. A scrum is most commonly awarded when the ball is knocked forward, or passed forward, or when a ball becomes trapped in a ruck or maul. Because of the physical nature of scrums, injuries can occur, especially in the front row.
what is the purpose of a scrum in rugby union
restarting play after a minor infringement