This refers to an injury to a prominent bone (usually the tibia) due to a direct blow. Bleeding occurs underneath the membrane lining the bone (periosteum) and inflammation follows. The blow is usually from a hard object such as a ball, stick or another player's boot. These injuries are common in hockey.
You will usually notice a definite injury during sport followed by considerable pain (the periosteum has a very good nerve supply). Most of the pain settles within minutes but a dull ache remains as bleeding occurs under the periosteum. A tender bump may be noticed on the bone. You should rest, ice compress and elevate the area as soon as possible after the injury to reduce bleeding.
If you think you have this condition it is well worth getting it checked as soon as possible by Mr Willis-Owen. Treatment involves resting and protecting the area while it heals. MRI scanning or x-rays are sometimes required to exclude other injuries.