Fractures and dislocations, but especially fractures, can be missed at any age but this is more likely in children or old people.

Children most often break their arms, legs or collarbones – a fractured collarbone is obvious but needs complex treatment. A child’s broken bone is usually detected because of greater pain than expected from the accident. The child is reluctant to move the limb or to allow it to be touched. Tenderness and pain on pressure is greatest at the fracture site.

A patient shouldn’t be moved if damage to the spine, whether back or neck, is a possibility, but otherwise immobilise the limb and take the child to hospital.

A fracture resulting in displacement or malalignment of the bone makes diagnosis obvious. There will often be swelling over the site, with bruising. If it is a comminuted fracture (where the bone is broken into more than two pieces), deformity and swelling are likely to be greater.

A simple fracture is one where there is a clean break and the overlying skin and tissue are not torn. An open fracture leaves the site of the bone exposed to infection.

A green-stick fracture in children is where the bone is bent and cracked, like a bent green branch, rather than snapped.

The object of any treatment is to restore mobility and prevent lasting deformity or damage to a joint adjacent to the fracture. Children’s bones heal more quickly than adult ones.

In the elderly, bones are fragile from osteoporosis, and failing eyesight and balance is poor so that spines and hips are frequently fractured. Careful examination of older people reveals that around a fifth have had compression fractures of a spinal vertebra that has collapsed. If the fracture has left the spine unstable or pressing on the spinal cord or nerves, urgent treatment may be necessary.

Hip fractures are sometimes initially undetected – with tragic results. Older people who fall should have hip joints tested. If the thigh bone has been fractured without initial displacement, the angle at which the ankle is held when lying flat provides the clue.