They Aren't What You Think...

I am going to be completely and 100% honest with you and up front right from the beginning - we in

the year 2021 still do not understand fully what a side stitch actually is. You're probably like

Justin - so what am I watching this video for? Well, I'm glad you asked because despite that,

I can still show you some of the theories - some of the ideas we have surrounding the side stitch

and we can look at the anatomy inside of the cadavers to try and piece this together. So,

it's going to be a fun one even if we don't really understand exactly what's going on. Let's do this!

First things first, let's make sure that we're all on the exact same page and we

understand what we're really talking about here. I actually grew up calling this a "Side

Ache". Maybe you grew up saying it's a side stitch or maybe you just called it a stitch.

Regardless of what you called it, what it is a sharp pain in your - typically your

lateral abdomen or on your side, therefore the side ache/side stitch. But in the scientific

literature, they actually call this ETAP - which is short for Exercise Related Transient

Abdominal Pain. And yes, that's a mouthful but it actually tells you a lot about what it is.

Exercise related, meaning that you find this typically with exercise. Specifically that's

usually running and swimming, although it can and does show up in other forms of exercise,

it's just going to be far less frequent. Transient shows that it just doesn't always show

up on the sides. It can actually be in different locations in your abdomen but by far and large, it

happens to be, for most people, that it is on the sides but that's where the transient comes from.

And then abdominal pain, obviously because it's in that abdominal region. So, now they're all on the

same page, let's go ahead and take a look at the cadaver and start to piece this together. So let's

go ahead and give you a quick tour of the area so you understand exactly what you're looking at.

So, this area here is known as the abdominal cavity and then you're seeing the lower portions

of the thoracic cavity just above it. Now, what's separating the thoracic from that abdominal cavity

is going to be this muscle here which is a hugely important player in our story today.

This is the diaphragm muscle. And the diaphragm muscle - diaphragm actually means

fence and that's what it's doing or partition - it's separating that lower

thoracic cavity from the upper abdominal cavity. Now, just resting on top of the diaphragm, you can

see the bottom portion of the heart and then you can also see some lungs on the sides here. Now,

if I scoot the diaphragm out of the way, we can see this massive organ which is the liver.

Now interestingly, just underneath the liver should be a gallbladder but this individual had

his removed. But if he did have it, you would see it nestled just underneath right there.

Now, also behind the liver - I'll do my best to show this to you, there's a pink organ here.

This is the stomach. This is also going to be an important player in today's story

and then to the left of the stomach is a really cool organ called the spleen and we

can pull some of it out of it for you to see. Then draping off of both the liver and of the

stomach is this fatty apron right here called the greater omentum, which is a really cool piece of

tissue that I can lift up which will allow us to see some of the transverse colon and I can also

pull some of the small intestine into view here. Before we talk about the different theories of

ETAP, we need to provide some kind of baseline - some common thread that each of those theories

are going to have with each other and that is the fact the stomach is going to be filled up

with something - you either ate something or you drank something.

I know when I grew up, I knew for a fact that I couldn't drink a bunch of water, for instance, and

then go running. That was pretty much a guarantee that I was going to get a side ache. So let's

go ahead and assume that that is the case. Let's say you drank a bunch of water. Let's say you did

exactly what I knew not to do and then you do some vigorous cardio such as swimming, for example.

So, the stomach, you can see it here, just pretend this thing is completely engorged. Now, one thing

you have to understand is that the stomach is not just floating there - it's going to be suspended

by various ligaments and soft tissues. So you can see one of them is the greater omentum.

Now, the greater omentum isn't really suspending the stomach as much as it's actually coming off

of the stomach, but behind it there's another tissue we can't see called the lesser omentum.

And then above it, there's all these different ligaments that are attaching the stomach to your

liver and to the surrounding structures. So, picture this engorged stomach

just being suspended, hanging there and then here comes you going for a swim.

And as you're going for the swim, it can start getting jostled around

and start tugging on all of those ligaments and those ligaments are going to have receptors inside

of them. And that they're - that which those receptors exist to provide feedback to the brain.

So what can also end up happening is saying like "Hey, we're getting tugged too vigorously" and

that can send painful noxious stimuli and that could possibly be that side stitch.

Another possible theory is what's known as an irritation of the peritoneum. So we have to

explain what the peritoneum is, obviously, and this is going to be pretty intuitive to you.

I want you to look at all of these organs in here and think to yourself "What would happen

if you went running", right? The liver is going to be bouncing up and down, the diaphragm is going to

be contracting like crazy as you're breathing, the heart's going to be bouncing on top of it, right?

All of these organs are just going to be jostling around. I mean, think like if you did

jumping jacks right now, just the chaos that's going to be going on inside of your body. So,

obviously, physics is still a thing and friction is going to be occurring between these organs and

tissues as they're rubbing against one another. Well, the body found a way around this or at

least to help mitigate it and that's through what are known as serous membranes. Serous membranes

secrete serous fluids and serous fluids help to reduce that friction as much as possible. So you

would have serous membranes coating the surface of organs as well as - I'm going to pull this

into view here - this is going to be our chest plate. You can see the abdominal region here with

abdominal muscles, this is going to be that belly button or the umbilicus and if I flip it over,

you can see that there is some tissue here. This is part of the parietal peritoneum.

And so, the parietal peritoneum is just going to be attached to the inside of your body, right?

That inner lining of your of your body wall. So you have two serious membranes, right? You have

the visceral peritoneum and then you have the parietal peritoneum and they're secreting

serous fluids to help lubricate so then they can slide past one another.

It's a brilliant uh, it's a brilliant idea here. So okay, so let's go ahead

and picture this again - if I bring out the stomach and I can - let's pretend again,

that stomach is completely engorged, you just filled it to the brim with water,

what can start to happen is it can start to irritate as you start running and moving, start

to irritate that parietal peritoneum and that's one of the ideas as to the causes of a side stitch

is that the stomach itself is irritating that lining and reducing the serous fluid ability,

that capability of producing it so you're getting more friction and that is resulting in more pain.

And the last theory I want to talk about is called diaphragmatic ischemia. Ischemia can

happen to any tissue in the body. This is when that tissue is experiencing a lack of oxygen

due to a lack of blood. So, let's go ahead and look at this diaphragm again and again, just

picture like you're running, the muscle fibers - hopefully you can see this, I'm gonna kind of try

and spread it out as best I can so you can see. Let's grab my probe here. The individual muscle

fibers, the muscle cells coming down here, those are going to be loaded with proteins that are

being contracting and shortening like this. That's what's going to be happening as you're breathing

but this is going to require a lot of oxygen. So we don't have the time to really go into this

in this video but this is cellular respiration, this is where you're using that oxygen to make

what's known as ATP or Adenosine Triphosphate - that's the energy that the cells are going to use.

Well, oxygen is going to be carried inside of the bloodstream and as you're contracting,

right? As all these are contracting, that might reduce blood flow to the area because

if you're breathing too heavily, too rapidly, too harshly and vigorously - I'm using like all these

descriptive words here - what could happen is you could have a reduction in blood flow to the

diaphragm muscle which could result in a lot - well, will result in a lack of oxygen which

will then lead to essentially what's a cramp. And if you have that cramp, that's obviously

going to hurt, because I'm sure you've experienced a skeletal muscle cramp of some sort at some point

in your life, all right? So just picture again, this is just going to contract it back and forth

until it can't really do much anymore and it just starts to cramp - well, I really should go like

this - it starts to cramp up and you're stuck in that position and that could create a lot of pain.

Now, there's another interesting thing that's associated with side stitches that

the diaphragmatic ischemia might help explain and that's called shoulder tip pain. Some patients and

individuals who have suffered a side stitch have described experiencing pain on their shoulders.

This could be a referred pain and referred pain meaning that the source of it is outside

of the shoulder but you are feeling that in the shoulder. And one of the ideas is it could be this

nerve called the phrenic nerve. Now the phrenic nerve - phrenic actually means

diaphragm. Phrenic is one of a couple nerves that actually goes to the diaphragm muscle

and causes it to contract as well as provides feedback information to the brain.

So think about this - if the muscle is cramping, it could make it so that - as

that phrenic nerve travels and goes up, it'll actually go towards the shoulders,

it could be sending a referred pain signal to the shoulders to provide that shoulder tip pain.

So now you're probably wondering "Well, which of these theories is the most likely culprit?"

and it kind of depends... Some of the literature will suggest it's more along the lines of the

irritation of the peritoneum, others will suggest that it's the pull of the visceral ligaments

and we used to think uh, that it was more of the diaphragmatic ischemia.

Personally, this is just my opinion, I'm just saying things... I have no skin in the game in

this, this is completely just anecdotal on what I'm thinking. I wouldn't be surprised

if it's some elements of all three or at least multiples of them. That just makes sense to me

because all of those things can actually be happening at the same time. So, personally I

wouldn't be surprised if it's gonna be elements of all three or elements of two of them,

that would just make a lot of sense to me. But you're probably wondering "Okay, well,

what do you do if you do experience a side ache or a side stitch?" honestly rest is pretty much all

you can do. Some people actually can push through it. I know I've personally pushed through it many,

many times, it's not enjoyable but it's doable. It doesn't tend to last that long,

just as most cramps don't tend to last that long and I do view this as somewhat of a cramp, but

rest is pretty much it. You just kind of have to wait it out and eventually everything will reset.

Thanks for watching everybody. I hope you enjoyed this video. I had a blast as usual filming it

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Thank you for watching and I will see you in the next video.