Five Questions

[Diane]

Here is the interactive site Bernard found that shows embryo formation. The very first section is about cell layers/differentiation.

Here is a link to the formation of mesenchyme thread, in the folder "In the Beginning" in the forum, Best Evidences. (I don't think it is visible except to members.)

(I think that is the one you mean, Barrett.. if not let me know and I will put on the scuba gear and dive again for a different thread.)

Happy to oblige. I love embryology. It is definitely good evidence for why we do what we do, why we have a better chance of being interactive with another person's nervous system through handling skin rather than trying to dive through it into some mesodermal target, impossible to do anyway without the skin's knowing all about it.

[stregapez]

Can we say that sensory disturbances to the mesoderm are far less likely to hurt than those to the ectoderm? If we can back this up it's a powerful statement not only about what we look for but why we treat as we do.

With all due respect, but I can't. It's not my experience, nor what I find around me with other people for the most part. I just had a conversation with my son's dad, who's a nurse about this. He also has had very instant painful ankle sprains (I had to check with him for fear i was losing my mind and memory) Just watch some TV sports (I hate them personally but it's a good example) When people get injured on the football/socker field you often see them doubling over in excruciating pain quite instantly (because they injured an aspect of the "mesoderm") I don't see how I can ignore that there are plenty of sensory nerve ending in bones, tendons, muscles, ligaments, joint capsules as well as skin and fascia...

It doesn't have to be one or the other, like a religion or something, does it?

The honest truth is "the mesoderm doesn't feel pain and/or isn't important" is about as true to me as "memory is stored in fascia" (ok, only about 75% as bad)

Dana , disagreeing with everyone equally (it's lonely here)

[Diane]

Dana, check out in an anatomy book (in the nerve section) the tight neural tunnels directly behind/in front of the ankles, wrapping around the heel, into all sides of the feet. Then defend the idea that it is the mesoderm that hurts when you "sprain" an ankle.

It makes sense that mesodermal structures (in general, ok? as a rule) don't hurt as much as skin. It gives the critter (human or non) who has fallen over a cliff and broken a bone or ripped a tendon or whatever, a chance to escape and find a place to hole up away from predators before the pain really hits, to sleep and heal.

It's nothing to do with religion, it's what makes sense.

[nari]

Dana

Injuring a ligament or joint without a direct trauma to the skin doesn't necessarily hurt much; it depends on the nature of the injury. I was surprised that a ruptured ligament in the distal end of a finger produced a great deal of swelling and colourful bruising, but it didn't hurt; it was simply uncomfortable for a day or so. A cat scratch, even if shallow, can be quite painful, and so can a tiny cut from a knife. Think of that feeling one gets when we slice a bit of ectoderm with the edge of a sheet of paper - a quite instantaneously perceived sensory event.

It gets confusing when it comes to therapy, because there is nothing we do that does not involve skin contact. It might help to recall that the brain has no receptors for noxious stimuli - the surgeons can fiddle happily with the exposed brain and it is painless. (For them and the patient!)

Nari

[stregapez]

Are you talking about cutaneous nerves, specifically?

Unfortunately I don't have a decent anatomy book with that detail, and can't find that online offhand.

I know there are at least some deep nerves in the area too.

If you can convince me I will believe and even prophesize, even if it isn't a religion (forgive me it's late here) but I'm not yet convinced.

I can't believe I spelled soccer wrong , though that's sort of appropriate i guess.

Dana

[Diane]

I don't see how I can ignore that there are plenty of sensory nerve ending in bones, tendons, muscles, ligaments, joint capsules as well as skin and fascia

Yes there are. But most of them just get to the cord and are handled there. The ones that get signals all the way to the cortex, rapidly, are the large myelinated ones from skin.

The thin unmyelinated/myelinated ones that are all through all types of tissues report all the time, and yes, if the structure gets broken/torn, pain will occur, but secondary to the inflammatory process set up to stop movement and heal the area, not so much from the actual initial primary tissue rippage, especially if skin is still intact.

I don't know what else to say, except, get reading.

[stregapez]

Nari,

We cross posted. While it's possible you're right, I was just talking (to my son's dad) about ruptures versus tears and we agreed tears are more likely to hurt lots than ruptures.... but maybe what I assumed or doctors told me were torn ligaments or tendons were actually curtaneous nerve trauma? I am not yet convinced of that but will consider the possbility. I did hear quite a loud pop last time.

Dana

[stregapez]

I don't know what else to say, except, get reading.

Ok, will do.

We cross-posted too.

Dana

[stregapez]

ps ~ I do much appreciate the dialogue/explanation.

D

[Luke Rickards]

Interesting thought. While I don't know whether stimulation to the ectoderm is associated with higher intensity pain perceptions, it is obvious that it is at least more sensitive.

I have put a lot of acupuncture needles into a lot of people over the years and it doesn't take long befor you realise that the most important thing about technique is to get through the skin quickly. Do this badly enough times and you lose the patient. Once you pass this you can twist and twirl and scrape away in tendon, muscle, ligament and peritoneum as much as you like and the patient usually feels very little, or at least the sensation is not distressing. But God help you if you accidently touch a peripheral nerve.

Luke

[nari]

Same with a cannula - smoothly and rapidly; those who go slowly so as not to hurt, hurt the most.

Dana,
I have heard that as well.
Rather like sprains, which tend to hurt more than fractures. I have no idea why but I'm sure the others all have answers.

Nari

[Diane]

Think of the skin as a two way street.
It is sensitive to what comes at the body from the outside, anything that would pierce through its integrity; needles, paper cuts etc. .. teeth, claws..
Why wouldn't the same nerves in the skin be equally sensitive to deformation from underneath? Especially in places where the skin is more tightly adjacent to boney joints? (Is it just me who thinks this way?)
I learned this in PT school at age 18.. with pressure sores. It's not so much the friction on the bedclothes that breaks skin down, it's the pressure of the bone out, out against skin from the inside that breaks it down by pinching it and depriving it of blood flow.
Since then, I've been interested in skin, what can I say? Without it we're goners.

In the case of sudden jolts to it from inside, forces hard enough to break a bone or actually rip some bit of mesoderm off some other bit of mesoderm, the skin may well get yanked too, depending on a multitude of factors and vectors and directions and variables... it is attached on its underside to the superficial fascial covering by little multidirectional moorings, many of which convey small diameter nerve/vessel. If one of those gets overstretched or ripped, don't you think there's going to be some pain involved, or bleeding/bruising of skin associated? It won't be so much from the mesoderm, but from these skin ligaments being ripped that one will "feel" immediate pain, if one feels immediate pain at all... otherwise, one will hear something or feel a dull "something" that's uncomfortable, and the brain will make you limp because of course, it will "know" even if your conscious (sensory cortex) awareness does not/has felt no sharp pain, and will act to protect the part, and of course later when healing has begun you will really feel that due to secondary sensitization.

Anyway, that's my story and I'm sticking to it..

[Barrett Dorko]

Consider the pain of a severe sunburn. Worse than a broken leg in most instances.

Dana, Nobody here is asking you to believe anything. In my opinion, clinical science should avoid belief as much as possible. Many of my students ask me if I don't believe in this or that and my answer - that when it comes to my clinical practice I don't think I believe anything, but rather that I understand things - is often unpopular.

[nari]

Dana

When you look at a diagram of the body in an anatomy book, look at the basic body, before it gets broken down into muscle and fascia and bones. Bare torso. Think about the cutaneous nerves that look like a tidy but complex spider's web in parallel and in series. Zillions of them.

Now think of that as the direct line to the brain; a super-efficient radar that is the forefront in the duty to protect the blob at the end of the brain (the body). Like the cat's whiskers - cut them off and the cat really can't function too well, and would fall off fences, etc.

The stimulus of a sudden impact on the skin, like running into a heavy object or skidding suddenly to a crashing stop as in baseball or football, sends off alarms++ that something is threatening the integrity of the organism/blob.

The fact that something is broken or torn underneath takes a while to set in.
Sometimes it takes days, if the organism has to run to a safe place or try to escape if it can't run....hence ongoing pain sometimes does not show up for up to 72 hours. (David Butler)

So when you massage someone, you are "talking" on a direct line to his/her brain. Pretty awesome when you think of it...

Nari

[stregapez]

Diane, I need to read the article on skin ligaments.

Barrett, I was partly being silly/joking there. As for the serious element I think it's party just semantics ~ What i meant is that if I somehow am presented with enough information that is believable to me my understanding may change.

How something should be "rated" in believability often is a big question for me too. There is sometimes the problem that information from seemingly "reputable" sources (eg Pubmed articles) contradicts, or maybe something Patrick Wall says will contradict with what some other pain scientist says (not sure about that yet), and i'm not a scientist so....How do I even know that when Wall, for example, states something , and cites *one* study (which he often seems to do) to back it up (one I don't have at my fingertips either) that I should even believe him (partly just an example, since i started to read on of his book)? Maybe these particular things we are discussing here re pain and skin vs mesoderm are more "cut and dried" then my limited knowledge would provide me (quite possible considering lack of training) but from what I gather so far it's not totally "cut and dried"

Dana