In the course of everyday life, most of us have suffered the pain of a solid bump on the head. Whether from a fall, a door or a low-hanging branch, that sharp shock is familiar. We can usually sit for a minute or put on some ice, and carry on. But from March 2003 to March 2004, more than 16,000 people were admitted to hospital in Canada with a head injury. Most of those injuries came from falls. The tally doesn't include people who were treated and released at doctors' offices or emergency departments

As well, an estimated 2,000 children a year suffer head injuries in tobogganing accidents. Health Canada has recommended that all children use a helmet when sledding. But no province has passed legislation requiring the use of a helmet while sliding down a snow-covered hill — although most have some kind of bicycle helmet law in place.

While helmets for hockey and lacrosse are regulated, others are not. A private member's bill introduced in the House of Commons would require all recreational snow sport helmets not approved by the Canadian Standards Association to be prohibited under the Hazardous Products Act.

When does a knock to the bean become a cause for concern and medical attention? Here are a few answers to common questions about head injuries.

What are the common causes of head injury?

Car accidents are a major cause of serious head injury. Other causes are falls, sports and assaults. You don't have to be hit on the top of the head — a blow to the jaw or side of the head can also cause a brain injury. People who have had previous head injuries are believed to suffer more serious repercussions when they have another. Another injury to the head before a person has fully recovered can lead to brain swelling.

What types of head injuries are there?

The four main types of head injuries are:

• Concussion: a mild brain injury that is usually temporary.
• Contusion: a bruise on the brain.
• Fracture: broken skull bones.
• Hematoma: a blood clot caused by a blow to the brain.

The head and brain can be injured whether or not the skull is actually damaged. A hard knock or jolt, even with no external sign of injury, is enough to cause a brain injury.

What are the symptoms?

Symptoms can range from none to mild pain at the site of the injury, bleeding or lack of consciousness. Indications that the injury needs medical attention include:

• Loss of consciousness.
• Continued headaches, and headaches that get worse.
• Nausea and vomiting, particularly in adults.
• Seizures.
• Confusion.
• Loss of memory of events surrounding injury.
• Drowsiness or lack of responsiveness.
• Blood or clear liquid from the ears, nose or mouth.
• Unusually large pupils, or pupils of different sizes.
• In infants, an inability to stop crying.

How should it be treated?

Many mild concussions don't require more than rest and monitoring. Someone else should watch for signs of more serious injury, though. Sometimes the symptoms of a serious concussion, a contusion or hematoma may not show up for days.

Monitor when the patient does not appear to have any signs of serious injury. Make sure the person with the injury is not confused or having trouble walking. Watch for symptoms listed above.

Call the doctor if the patient later experiences dizziness, repeated vomiting, difficulty concentrating, or changes in personality.

Call an ambulance if the patient has lost consciousness, or is having seizures, paralysis, or problems walking or talking. If it is a small child, call the doctor if you think the child is not behaving as usual.

If the person has a skull fracture, put a bandage on the wound but do not try to clean it out or disturb it in any way. If the injury is serious, call an ambulance and do not try to move the patient.

Someone with a serious head injury is likely to be admitted to the hospital for treatment and observation. Symptoms can take days to show themselves. Surgery may be required to relieve pressure on the brain, if there is swelling or bleeding.

When can normal activity resume?

This will depend on the seriousness of the injury. Be sure to wait until all symptoms are gone. After a mild concussion, some people can resume normal activity almost immediately. Ask a doctor how long to wait after symptoms are gone.

Can they be prevented?

Most injuries can be prevented by sitting quietly at home — but people don't want to live their lives that way. But a few simple steps can drastically reduce the risk:

• Don't drink and drive.
• Wear a helmet when biking, inline skating or snowboarding.
• Wear a seatbelt in the car and make sure children are in safety seats.
• Slip-proof your home, especially the bathroom.
• Play sports responsibly, using the proper equipment.

Children and helmets

One of the challenges parents face in protecting their children from head injuries is persuading them to wear a helmet, even when an adult isn't watching over them.

Ellie Wannamaker, a member of the Canadian Physiotherapy Association who treats children with head injuries at Bloorview Kids Rehab in Toronto, has some tips.

• Convince them that wearing a helmet is "cool" by pointing to people like cyclist Lance Armstrong or other popular athletes.
• Have children participate in the selection of the helmet, If they like Spiderman and he's on the helmet, they're more likely to wear it.
• Get the whole family to wear helmets. If parents don't wear them, children are less likely to stick with them through their teens and into adulthood.

Wannamaker says a general guideline is that children should wear a helmet whenever they are going faster than they can run — using roller skates, inline skates, bikes, skateboards, scooters, skis, snowboards, toboggans, etc.