Head Injuries in Anime part 2- Hematomas

Head Injuries in Anime Part 2- Hematoma

In part one of Head Injuries in Anime I explained how all those bumps on the head our favorite anime characters receive can be a lot more than just simple bruises, such as a variety of skull fractures. There are of course a number of head injuries beyond bruises and skull fractures, like hematoma and concussions, which have been in the news a lot over the last several years, due in part to the NFL and other collision sports.

Warning: Extra Science Content

You might be wondering why I used the term collision sport instead of contact or full contact sport. This is because the American College of Pediatrics released a statement in 2008 that redefined their view of contact in sports.

“In collision sports (eg, boxing, ice hockey, [American] football, lacrosse, and rodeo), athletes purposely hit or collide with each other or with inanimate objects (including the ground) with great force. In contact sports (eg, basketball and soccer), athletes routinely make contact with each other or inanimate objects but usually with less force than in collision sports. In limited-contact sports (eg, softball and squash), contact with other athletes or with inanimate objects is infrequent or inadvertent.”


Basically, collision sports are sports where you are supposed to hit the other player as a course of playing the game, while full contact sports are sports where you might hit the other player in the course of the game, but the contact is not part of the game itself.

Extra Science Content over

If you are wondering what all of this has to do with anime, the answer is a lot. How many times have we seen an anime character get hit and sent sprawling to the ground dazed and/or unconscious? This knocked out state is often depicted with white pupil-less eyes or swirling eyes.

unconscious Unconscious

There are many terms for this state: shaken up, getting your bell rung, dinged, and getting your cage rattled. The choice of words really doesn’t matter as they are all referring to the same thing, concussion. But before we get to concussions, there is one more head injury that is worthy of mention, even if its occurrence in anime is even less than a potential fractured skull.


All of you have probably had a hematoma or, as it is called in layman’s terms, a bruise. A hematoma usually forms as a result of an impact or injury, but diseases can also cause them as well. How bruises form is fairly simple in that the blood vessel needs to break but the skin above the blood vessel does not; this means that the blood leaking from the blood vessel stays trapped inside the body.

Real bruise
bruise in anime

You might be thinking what does all of this have to do with the brain? Think about the last time you had a bruise and you might remember that a bruise and the swelling associated with it caused a bump in the area the bruise is located. A bruise on your leg has some room to swell and grow as its surrounded by skin, fat, and muscle tissue that is fairly pliable. Now imagine if that bruise was inside your skull where your brain is located. Bone is a rigid tissue that is not going to compress or be pushed out of the way. This means that the brain is going to be compressed as blood bleeds into the inside of the skull.

Brain Hematoma

Like skull fractures there are several different types of brain hematomas, but they are all the result of broken blood vessels leaking blood inside the skull. The differences come from where the bleed is located and for that we need to go back to the meninges that I discussed in the previous post and have highlighted below.

Epidural Hematoma

An epidural hematoma occurs when the bleeding occurs between the skull and the dura matter. This particular injury is more common in children, but it can happen in adults as was the case with Natasha Richardson, a well-known British actress who passed away from an epidural hematoma in 2009, following a skiing accident. An epidural hematoma is caused by trauma to the head which causes the skull to fracture (85-90% of the time) and arteries to rupture, causing bleeding between the skull and the dura mater. Due to the bleeding’s being caused by an artery the swelling occurs rapidly, which quickly puts pressure on the brain.


Symptoms of an epidural hematoma include the following: confusion, dizziness, altered level of awareness, enlarged pupil, headache, loss of consciousness, nausea or vomiting, and weakness in part of the body. While any blow to the head with a significant amount of force can potentially cause an epidural hematoma, blows to the side of the head or the temple are more likely to cause one. This is because the temporal bone of the skull is thinner, and the middle meningeal artery sits inside of it with little to no padding. This means that it is easily ruptured from a blow to the side of the head. If you have ever played or watched baseball, you have probably noticed the shape of the baseball helmet. Here is a picture for those you who haven’t:

Notice how the helmet comes down around the ear, completely covering the side of the head, and providing extra padding if an errant pitch hits the player in the side of the head. It’s still going to hurt if you get hit, but its not going to kill you, which has actually happened. In 1920 Ray Chapman (Cleveland Indians) was hit in the head by a pitch from Carl Mays (Yankees); he was assisted off the field and died 12 hours later. It was this incident that started the discussion on safety gear for baseball, but it would be another 30 years before helmets were required.

As always, I do have an anime connection, and this time it is Samurai Champloo, which does have a baseball scene despite being a Samurai anime. During the scene in question Mugen throws the ball at the player’s head and hits him hard enough to instantly knock the player out.

epidural hematoma

We can also see that the ball is impacting the side of the and, while it is a bit lower and more towards the front of the head than what might cause a typical epidural hematoma, but the player is still knocked out by the blow. I would also say that there is a very good chance that Mugen might have given the player an epidural hematoma, which more than likely killed the player, due to the state of medicine during the time period (Edo 1603-1868) in which the anime takes place.

The treatment for an epidural hematoma involves surgery. Specifically, a craniotomy, which involves removing a piece of the skull in order to give the swelling a place to go besides crushing the brain. The location of the surgery will vary depending on where the hematoma is located. Ideally the skull is removed in the area above where the bleeding has occurred so the swelling pushes out of the hole instead of the brain. After the bleeding stops and the swelling has reduced, the hole in the skull is filled in. Ideally the bone that was first removed is put back into place, but metal plates can be used instead.

Subdural Hematoma

A subdural hematoma occurs when the bleeding is located between the dura mater and the arachnoid mater. While less serious than an epidural hematoma, it is still a severe injury, and the danger is connected to how fast the bleeding is occurring. Generally subdural hematoma’s take longer to progress because the brain is filling with venous blood, which is lower pressure (slow bleeding) than arterial blood (faster bleeding). The faster the bleed the quicker the inside of the skull fills up with blood, putting pressure on the brain. Some of the main symptoms include pain, numbness, weakness, dizziness, and disorientation. Now think of how many times we have seen an anime character take a blow to the head and wind up confused and disoriented as a result.(We’re looking at you Sakura and Naruto)

subdural hematoma

Yes, I know that Naruto has some sort of crazy healing factor, but if he didn’t, Sakura probably would have killed him by now, and what about all of those people that she punched who didn’t have crazy healing factors? For those people who do not have healing powers the treatment is similar to an epidural hematoma, stop the bleeding, and reduce the pressure from swelling.

Subarachnoid Hemorrhage

A subarachnoid hemorrhage is bleeding in the subarachnoid space between the arachnoid mater and pia mater. The reason it is called a hemorrhage instead of a hematoma is that a hematoma is a collection of blood due to bleeding that has stopped, while a hemorrhage indicates bleeding that has not stopped. Like our previous injuries subarachnoid hemorrhages are often caused by a forceful blow to the head, but they can also be caused by certain diseases, and other conditions, like a ruptured aneurysm.

The symptoms of a subarachnoid hemorrhage are similar to the symptoms of the injuries that were previously discussed including: splitting headache (the worst a person has ever had), neck pain, numbness throughout your body, shoulder pain, seizures, confusion, irritability, sensitivity to light, decreased vision, double vision, nausea, vomiting, and rapid loss of alertness. It is the last symptom that is the most telling to none medical professionals. Often times it can appear in the following scenario.

Person number 1 hits person number 2, who then appears dazed but otherwise fine, no harm done, right? Person number 2 then says some gibberish and proceeds to pass out (for some reason anime does not include the headache). Now how many times has this happened in anime?… Hint: it’s a lot, especially in harem comedy shows, especially ones written by Ken Akamatsu.

subarachnoid hemorrhage subarachnoid hemorrhage

The treatment for a subarachnoid hemorrhage is the same as the other injuries I’ve previously covered: stop the bleeding, and reduce the swelling. In the case of a subarachnoid hemorrhage, it can involve surgery and various medications that are beyond the scope of what I do here at anime science 101. On a final note the overall prognosis for a subarachnoid hemorrhage is not particularly good with a 40-50% mortality rate. It does boggle the mind, then, that the Akane Tendo, Naru Narusegawa, or Kamiya Kaoru haven’t killed anyone yet.

Real World Connection

Ginzo Matsuo (1951-2001) was a voice actor who performed in a number of roles dating back to 1985. His most well-known roles were Hemu-Hemu in Nintama Rantarō and Ginnosuke Nohara in Crayon Shin-chan. His most recent role was Captain Smoker from One Piece, which was the role he was performing (episodes 1-93) when he passed away from a subarachnoid hemorrhage. I did try to find out the cause of his subarachnoid hemorrhage but I was unsuccessful. If I had to speculate I would say he had a cerebral aneurysm (a swelled blood vessel) that ruptured.


I think it’s pretty obvious by this point that I have yet to see an anime that correctly portrays any sort of intracranial bleeding regardless of where it is located. In most cases these types of injuries or blows that could result in the injuries discussed in this post are played for comedy more than anything else. FYI- I know I didn’t get to concussions yet, but the post just had a way of growing to include more of the intracranial bleeding injuries than I expected. Stay tuned for more on head trauma in anime and I promise the next one will be on concussions.  Please leave any comments or quesitons below.

2 thoughts on “Head Injuries in Anime part 2- Hematomas

  1. Pingback: Anime Science 101- Head Injuries in Anime- Part 1- Skull Fracture

  2. Pingback: Anime Science 101- Head Injuries in Anime- Part 3- Concussion

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