Head restraints

Effective head restraints reduce the rearward motion of the head in a rear-end crash and reduce the instance of whiplash neck injuries. Head restraints are commonly referred to as head rests.

What is a whiplash injury?

When a vehicle is hit from behind, it is accelerated forward, along with the body of any occupant. When this occurs, the occupant’s head extends backward from the torso, continuing in this direction until the normal extension limits of the neck are exceeded. Then the occupant’s head is accelerated forward from the neck.

The sudden and violent movement of the head in this backward and forward direction is known as ‘whiplash’ (as it is similar to the movement of the tip of a whip).

Extreme movement of the head being thrown backward and forward over-extends the neck’s normal movement range, affecting the ligaments and muscles of the neck and shoulders, and potentially causing injury.

Common symptoms of whiplash

A common symptom of whiplash injury is neck pain due to mild muscle strain or minor tearing of muscles and/or ligaments.

Minor whiplash neck injuries are usually associated with pain and limited motion of the head and neck.

In more severe cases, this type of neck injury may include nerve damage, disc damage and, in the most severe cases, neck ligament ruptures and neck bone fractures.

Preventing injury with properly adjusted head restraints

In a rear-end crash, correctly adjusted head restraints can limit the backward and forward motion of the head and help minimise whiplash injury.

To help prevent whiplash, adjust the head rest so it is:

• at least as high as the head's centre of gravity (e.g. eye level or higher) or about 9 centimetres below the top of the head
• almost touching the back of the head, or the gap between the head and the head rest is as small as possible.

Also check the angle of the seat back, as it might need adjusting to move the head rest closer to the back of the head. Gaps of more than 10 centimetres have been associated with increased whiplash injury symptoms in crashes.

A well-adjusted head rest is a very important piece of safety equipment in a vehicle. Read the vehicle’s owner manual for more information about adjusting head restraints.

Read about other checks and adjustments to do before you drive.