The terminology used in mild head injury can be quite confusing: three terms, mild head injuryconcussion and mild traumatic brain injury are often used. Most of the time theses words are used to mean the same thing, but they can each mean something a little different.

In this video, Professor Alan Carson explains the different terms used for mild head injuries and their definitions:

mild head injury is any form of injury to the head and does not need to involve any injury to the brain which is protected inside the skull cavity. Many of us sustain head injuries regularly- banging our head off shelves or when reaching under tables. Beyond being left with a ‘bump’, perhaps a headache and maybe feeling dazed for a second or two there is no loss of consciousness and the brain is unaffected.

In a mild traumatic brain injury our head and our brain are injured. Brain injuries show themselves by loss of consciousness. The person falls to the ground and is knocked out. This is usually only transient, lasting for a few seconds, but can be for 5 or 10 minutes. The person then ‘comes too’ but is often confused as to where he or she, what the time or the date is or who the people are around them. There will be a gap in memory from just before the head injury until the person fully recovers which is usually a few minutes but can be as long as 24 hours- the length of time from the head injury until this memory gap is over is referred to as post traumatic amnesia.

Concussion is another term for a head injury which also affects the brain. The patient may be knocked out completely or may only be dazed. He or she will show some signs of ‘lowering of consciousness’ and may confused as to what day it is or where he or she is. There may be signs of loss of co-ordination and the person may stagger slightly or have symptoms like ‘seeing stars’.

Read more about the assessment of head injuries

Does this mean I am brain damaged?

Common causes include:

  • Road traffic collisions
  • Falls
  • Assaults
  • Accidents in the home or workplace
  • Sports injuries


In the first days after a mild head injury it is normal to experience symptoms like headache, dizziness, fatigue and poor concentration. Usually, these symptoms settle within days, weeks, or at most several months.

Find out more about common symptoms 

If symptoms persist longer than would be expected from the nature of the injury, this is called post concussion syndrome.

Find out more about post concussion syndrome