At the outbreak of World War I, none of the combatant nations provided steel helmets to their troops. Soldiers of most nations went into battle wearing cloth or leather hats that offered little protection from modern weapons. As a result, many soldiers suffered head injuries from exploding shrapnel.
In April of 1916, British soldiers began using a metal helmet in battle called the Brodie helmet, but authorities discovered that the proportion of head injuries then increased. Why should the incidence of head injuries increase when soldiers wore metal helmets rather than cloth caps? Click below to see the answer.
The number of recorded head injuries did increase after the introduction of the Brodie helmet, but the number of deaths decreased. Prior to the introduction of metal helmets, if a soldier were hit in the head with a piece of shrapnel, it would have likely killed him. This would have been recorded as a death, not a head injury. More head injuries were recorded after the helmets were introduced due to the simple fact that more soldiers were surviving them.