for which reasons ,we should get a tetanus injection?

Tetanus is a bacteria that lives in soil and dust. You can get an infection through a break in the skin. It's a really nasty disease. Your muscles spasm and lock up, sometimes hard enough to break bones! It can take months to get over, and some people die of it.

Luckily we have a vaccine for it so you're much less likely to get it. You get the vaccine when you're a kid and then you get a 'booster' every ten years.

To prevent contraction of Tetanus.

Any injury that may have been comtaminated with dirt will require a shot, to protect you from full-blown tetanus. The prevention is MUCH better than the treatment for the disease. Doctors do not like to take chances.