How Helmet Protect Head Injury

These three functions are achieved by combining the properties of four basic components of the helmet that are described as:

1. The Rigid Outer Shell

   This is the strong outer surface of the helmet that distributes the impact over a large surface area, and therefore lessens the force before it reaches to the head. Although the shell is tough, it is designed to compress when it hits anything hard. It provides protection against penetration by small, sharp and high speed objects.

2. The Impact Absorbing Liner

   This is made of a soft, crushable padded material usually expanded polystyrene. This dense layer cushions and absorbs the shock as the helmet stops and the head tries to continue moving.

3. The Comfort Padding

   This is the soft foam-and-cloth layer that sits next to the head. It helps keep the head comfortable and the helmet fitting snugly.

4. The Retention System (Chin Strap)

   This is the mechanism that keeps the helmet on the head in a crash. A strap is connected to each side of the shell. Chin and neck straps, which are specifically designed to keep the helmet on during an impact, must be correctly used for the helmet to function as it is designed to.