Bone bruise is not an 'official' medical term. (Doctors prefer fancy Latin terms like edema.) It refers, as you might expect, to pain or soreness that seems to come from a deep injury on or near the bone. It is often accompanied by a sensation of contusion or swelling, often on an area like an elbow, shin or pelvic bone. It sometimes follows a 'compressive injury' (a.k.a. 'a good solid whack') but other times no specific incident seems to cause it.
A bone bruise may reflect an actual injury to the periosteum, which will calcify and heal over time. It may also reflect any number of other causes. Unlike a surface bruise it is very difficult to see and identify the problem, in the absence of a fracture or other problem which an x-ray or ultrasound will reveal.
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