Bone bruise (contusion)

What it means

Bone is not solid all the way through — its inner spongy layer is filled with marrow, blood vessels, and soft tissue. When a joint takes a direct blow, twists sharply, or two bones compress against each other briefly, small blood vessels inside that spongy layer can rupture. The result is bleeding and fluid buildup within the bone itself, known as a bone bruise or contusion, even though the hard outer shell of the bone stays completely intact with no crack running through it.

Why it appears on a CT or MRI report

MRI is the only imaging test sensitive enough to reliably show a bone bruise, appearing as an area of increased fluid signal within the marrow, often described as bone marrow edema. Because it does not involve a visible break, a bone bruise typically will not show up on a plain X-ray or, usually, on CT, which is why it is so often found on an MRI ordered after a knee, ankle, or wrist injury that looked unremarkable on X-ray. Reports commonly note its location, since the pattern of bruising can hint at how the injury happened — for example, matching bruises on opposite sides of a joint can indicate the bones briefly compressed together during a twisting injury.

What it usually means

A bone bruise reflects real impact to the joint, so it is often found together with other injuries from the same event, such as a sprained ligament or a torn cartilage, and the report may describe those alongside it. On its own, a bone bruise is a milder injury than a fracture: the underlying bone structure remains sound, and the marrow simply needs time to reabsorb the trapped blood and fluid. Most heal without any specific treatment beyond rest, ice, and protecting the joint from repeat impact while the marrow settles, though recovery timelines vary with location and how much of the bone is involved.

When to follow up

An isolated bone bruise found after a minor injury is usually not urgent and is appropriate to manage with rest and a routine follow-up appointment, particularly if pain is already improving. Get it checked sooner if pain is severe, if you cannot bear weight or use the joint at all, if swelling is significant, or if the report mentions an associated ligament or cartilage injury, since those companion findings — not the bruise itself — are usually what determine whether bracing, physical therapy, or further treatment is needed.

A plain-language way to picture it

Think of the difference between dropping a bag of flour and dropping a ceramic plate. A bone bruise is like flour settling and clumping after a jolt — internally disturbed and a little tender, but the bag itself is still in one piece and will settle back down given time. A fracture is the plate cracking clean through. Both can hurt, and both come from impact, but only one has actually broken the structure itself.