You can only treat well what you've seen. And you only see what you look for, in order.
ACT
Before touching anyone: look at the scene. Whatever hurt this person can hurt you too. Falling rocks, a cable on the ground, smoke, an unstable vehicle, an animal. An injured rescuer makes two casualties and no rescuer left.
Then, in this order. Never skip a step to go and look at the most spectacular injury.
- Consciousness. Speak loudly, gently shake the shoulders. No response: go to Unconscious person immediately.
- Breathing. Head tilted back, chin lifted. Look at the chest, listen, feel, for ten seconds. Absent or abnormal: chest compressions without delay.
- Bleeding. Run your hands over the whole body, including under the back and under dark clothing. Blood doesn't show on dark fabric; you feel it. Any bleeding you find gets pressure before you go on: see Severe external bleeding.
- Temperature. Burning-hot skin and disturbed consciousness: Heatstroke. Cold skin, shivering or no shivering: Hypothermia. Either way, it's already an emergency.
Only then comes the full examination, head to toe, on a stable person. Useful anatomical landmarks are in Anatomie fonctionnelle.
- The head. Feel the skull, look for blood in the hair, look at the pupils, ask whether their vision is normal. Fluid coming from an ear or the nose: serious injury.
- The neck and back. Ask about pain before moving them. Tingling, weakness or loss of feeling in a limb: don't move anything else.
- The chest. Do both sides rise together? Pain when breathing, trouble speaking in one go.
- The abdomen. Feel all four quarters. A belly as hard as a board is a serious sign.
Depending on what you find, see Poisoning for poisoning, Head injury for a blow to the head, Feeling faint and chest pain for chest pain.
- The pelvis and limbs. Deformity, swelling, pain at one precise point. See Fractures, sprains and splinting.
- Hands and feet. For every injured limb: is the skin warm and a normal colour, can the person feel your fingers, can they move their toes? Note the answer; you'll compare with it later.
Ask questions, if the person can talk. What happened, where does it hurt, since when, do you have a known illness, are you on any treatment, have you eaten recently, are you allergic to anything.
Write it down. The time, what you found, what you did. Over several hours, it's the change that tells you something, and memory distorts the timeline.
ADAPT
There are several casualties. Do a very quick first pass on everyone before treating anyone: consciousness, breathing, bleeding. The one who's screaming is breathing and isn't the most urgent. The quiet one comes before the loud one.
You're alone with a seriously injured person. Steps that hold without you — pressure kept on by a bandage, the recovery position, a blanket — free you to go for help or signal. See Signaling and getting found.
The person refuses to be examined. A conscious person has the right to refuse. Stay, watch, offer again. A refusal that turns into confusion is a medical sign in itself.
It's a child. The examination is the same. Behaviour tells you more than words: a child who plays and reacts is reassuring; a child who is unusually quiet, hard to wake, or refuses to drink is an emergency.
You find nothing wrong. Examine again twenty minutes later. Many internal injuries only show after a delay, and it's the comparison between two examinations that reveals them.
UNDERSTAND
The order isn't a teaching convention: it follows how fast each failure kills.
Without air, the brain suffers within minutes. Without circulation, within the same time. Massive bleeding also empties a body within minutes. Hypothermia or heatstroke kill within tens of minutes. A fracture can wait hours without further harm.
Treating in a different order means caring for what could wait while the rest collapses. It's the most common mistake of untrained rescuers, and it's perfectly understandable: an open wound catches the eye, while missing breath makes no sound.
Second principle: an assessment is a photograph; monitoring is a film. A single examination doesn't tell you whether the person is improving or getting worse. Repetition is what has diagnostic value, and that's why you note the time.
Third principle, counter-intuitive: a casualty who talks a lot reassures you wrongly. Speech proves that air is getting through and the brain is getting blood, which is excellent — but it says nothing about internal bleeding in progress. Someone can talk normally and then collapse all at once when the body's compensation gives way. In young, healthy adults, this compensation is very effective and hides how serious things are for a long time.