The day I posted “Do I Have A Purple Eye?“, a friend of mine made the following comment on Facebook:
Aha! You, sir, are incorrect. You forgot cerebral contusions which don’t leak into skin tissues but into surrounding brain tissue.
Well, this got my attention (and made my skin crawl). More importantly, it got me looking deeper into this whole ‘contusion’ thing. Buckle in, folks: this will be uncomfortable.
Not all hematomas are created equal
To begin with we’ll need to revisit some definitions, because I wasn’t entirely correct. Broadly speaking all bruises are hematomas, but not all hematomas are bruises. This is because a hematoma is just (“just”) a collection of blood outside the blood vessels, which can be caused by trauma, illness, or just the blood vessel tearing from weakness. Contusions are a specific subset of hematoma caused by blunt trauma.
According to Wikipedia, hematomas come in several flavors. These include:
- Subdermal, which is a hematoma beneath the skin.
- Skull/brain, which are hematomas where blood pools either within the brain itself or in the cerebrospinal fluid that cushions your brain within your skull. Subdermal hematomas of the scalp also get classified as skull/brain hematomas.
- Breast, which is a hematoma within the breast tissue – meaning that women are much more prone to these than men.
- Myocardial, which is a hematoma in your heart muscles.
- Pulmonary, which is a hematoma in your lung tissue.
- Subconjunctival, which is a hematoma of the conjunctiva – the tissue that lines the inside of your eyelid and covers the whites of your eyes.
- Perichondral, which is a hematoma of the ear. Specifically, it is blood pooling in such a way that the ear cartilige seperates from the perichondrium (the connective tissue that surrounds the cartilige of developing bone). This is where so-called “cauliflower ear[https://en.wikipedia.org/wiki/Cauliflower_ear]” comes from.
- Perianal, which is a hematoma of the anus. This is also known as a hemorrhoid.
- Subungual, which is a hematoma beneath a fingernail or toenail, and is sometimes known by names such as “runner’s toe” or “skier’s toe”.
Hematomas are also classified by degree. A petechiae is less than 3 mm in diameter, a purpura (which I mistakenly thought was a type of hematoma, instead of a degree) is between 3 mm and 1 cm in diameter, and an ecchymosis is larger than 1 cm in diameter. So a petechiae subdermal hematoma is a tiny thing on your skin, while a perianal ecchymosis is no diagnosis you ever want to have.
Now, a contusion is just (just?) a hematoma caused by our old friend blunt force trauma. So, really, any type of hematoma can be a contusion. Myocardial contusion? Sure. Perianal contusion? Yep. Perichondral ecchymosic contusion? Why not.
So there you have it. Anything that has blood vessels in or near it can suffer a hematoma. Skin, heart, lungs, eyes, whatever. And now I’m going to pack myself in cotton for a while. Just until the skin crawling and the paranoia wears off.