A broken bone and any damaged blood vessels start to repair and heal themselves immediately. A fracture in a long bone, such as the collarbone, normally takes about 6 weeks to heal in an adult. However, some injured bones may not regain their full strength for several months, and healing may need to be aided by a plaster or resin cast or by mechanical fixation. In children, fractured bones usually heal more quickly.
A clot forms to seal broken blood vessels. Gradually, a mesh of fibrous tissue forms and starts to replace the clot.
New, soft, spongy bone called callus develops on the framework provided by the fibrous tissue, joining the broken ends.
Dense, compact bone gradually replaces the callus, and blood vessels regrow. Eventually, the bone regains its shape.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.