Synovial Folds: The Hidden Cause of Neck Pain? | Podcast Ep. 339

Foreign hello and welcome to the Evidence Based Chiropractor. I AM your host, Dr. Jeff Langme. Today's episode we are taking a look at a landmark study. If I don't say so myself. This is from 2011 in the Journal Manual Therapy and it is all about synovial folds. A pain in the neck. That is the title. It will drop a link down in the episode show notes and this is potentially one of the most complete papers analyses that I have ever seen regarding synovial folds. I'll take away some of the big high points that I noted reading the study. I'm also going to encourage you again to check out that link below because it is a good one. Before we get started, I want to say a few words about the smart chiropractor. The smart chiropractor can power your patient journey to provide you with more qualified leads, more new patients, better, better retention and consistent reactivations without spending any money on advertising. Let's face it, paid advertising generates cold leads that you need to convert. They are the lowest quality patients. What generates the highest quality patients? Putting out consistent high quality content and attracting more of your ideal patients. That's what we help you do with the smart Chiropractor. It's about teaching and inviting consistently. You can check it all out@thesmartchiropractor.com again that is the smart chiropractor.com but as I said at the top, today's focus of the show is all around synovial folds. Synovial folds of the cervical spine are regarded as a potential source of neck pain, headache. They can be affected in whiplash injuries, slip and falls. And a lot of times when we're trying to gap the facet joints, put motion segmentally into an area. The synovial folds within the facet joints play a critical role. So this is something us as chiropractors we deal with each and every day in our practice. Yet I think sometimes they're overlooked. Checking out this study, there was a lot of great information that I wanted to share and that's what we'll dive into. So intra articular synovial folds, they're formed by the synovial membrane or the synovium that projects into a joint cavity and and are found in all of the articulations across the vertebral columns. That's sort of just what they are at a top line level. Now here's something I didn't know right off the top. There are three parts to a synovial fold. I Had no idea. A base, a middle part and an apex. Three distinct parts. The peripheral base extends from the fibrous capsule and tapers to form a thin apex that projects between the surfaces. The articular surfaces in cervical vertical synovial folds typically extend 1 to 5 millimeters between the articular surfaces and occasionally extend even more than 5 millimeters from their base into the joint cavity. So important to keep in mind, right there we have a thick base. It thins out towards that apex 1 to 5 millimeters, roughly in length. And again they sit between those articulations. So the number of. Here's an interesting fact as well that I did not know until I read the paper. The number of synovial folds decreases with increasing age, but does not appear to be influenced by gender. So I haven't really put together. There's something to this in terms of the number of synovial folds decreasing with age, yet restriction typically increasing with age. But I haven't put together exactly my thoughts. They don't dive into it in great detail in this paper. But there's something to be said about that. We know that as we age that the instantaneous axis of rotation, that pinpoint of motion where most motion first occurs at every segment, migrates posteriorly. That ends up loading the facet joints as we age, which is why we see facet hypertrophy as we get older. There's something to this that tying into the decreasing number of synovial folds. But I'm not exactly sure. Maybe a good topic for a future research study. Now, when you take a look at cadavers, there are basically three histologies associated with or histological compositions associated with synovial folds. Adipose, fibro, adipose and fibrous. Again, interesting to me, I thought synovial folds. A synovial fold is a synovial fold. Not the case. There are three distinct types or, you know, histological composition types associated with this. And again, that's adipose, you know, mostly fat, fibro adipose, sort of that mashup or cross link and then fibrous itself. So fascinating. As we dive in, again we hear these synovial folds or the facets. Whether it's decreasing pressure or increasing pressure depends upon who you ask. But as we're delivering the adjustment, we hear noise, right? We hear the pop, the crack. Typical thing associated with the spinal adjustment. And synovial folds no doubt play a role in that. How big of a role? Good question to be answered. So let's take a look at some of the Previous research around synovial folds because it sort of sets the stage for where we're at today. Synovial folds are not or appear, I should say, to not be innervated. Interesting. If you don't have innervation, well, it's hard to have pain. Right. So they are not innervated. But the presence of nerve fibers and endings has been demonstrated in some recent studies. So early studies not innervated. Newer studies appear to potentially be innervated. Very interesting as we dive into it. And I think there has to be some innervation as we talk about the sensorimotor components of which I think for set joints and synovial folds do play a role. So nerve fibers have been identified alongside and independent of the blood vessels in the synovial folds. But there's very little to no agreement on the function of these nerve fibers. So are they proprioceptive, are they vasomotor, are they nociceptive? Nobody seems to be able to agree on that yet. But we do know that there are some nerve fibers and nerve endings going into these synovial folds. I think it's going to have to do with proprioception. It might have to do with pain as well, to be determined. So synovium and the synovial folds, of course, they sit within these spaces, these articular spaces. So they're believed. And I don't think this is a stretch. I think they probably do adapt themselves to the contour of the joint space in all positions and they act as sort of the passive space fillers. They use that term in the study. I love it. Passive space filler that fill the non congruent points of a joint in its neutral position, but displaced when the joint moves. So the synovium is in its most natural position when the joint is in its most neutral position. That makes a lot of sense to me. The other thing is I think about this in surgical intervention cases a lot. And I always say the body doesn't like extra space, right? It's going to fill space with something. If you do a surgery, it's typically gonna fill space with fluid or scar tissue. If you're taking bone and ligament out, the body doesn't like open space. It will fill that in again with scar tissue. It'll fill it in. The doctor might fill it in with bone. It could fill up with fluid. Very, very common, all of those after a surgery. In the case of a joint, non surgical intervention, of course, the joint itself, again, the body doesn't like open extra space. So it makes so much sense to me that the synovial folds fill in and act as that passive space filler. I never considered whether it's in its neutral state or natural state when the joint's neutral or moving. Interesting point that when the joint's in the neutral state, the synovium is in its most natural state and then it deforms to fill in the space as the joint goes through motion. Very, very interesting. It's also been suggested that these synovial folds can protect and, or lubricate the articular surfaces and, and assist in weight bearing, maybe dissipate stress. All of these things. I believe when we think about it, you think about synovial folds and how they act specifically in the spine make a lot of sense to me. And there might be that mechanosensory role. And I think we've seen that with some of our joint position studies as time has elapsed since this study came out about a decade ago. So it's believed at this point that they can provide proprioceptive feedback, sensory motor control, and this could be especially important. I think we've seen this in some updated studies in the upper cervical spine, which has that direct neurophysiological connection to the vestibular and visual system. So as we get up towards that brainstem, that upper cervical spine, positioning of the joints, of course, matters tremendously. But also the ability to have fluid motion and the ability for the synovial folds to act as normally as possible is super, super important. Now here's something that was totally new to me. The synovium and adipose tissues can release growth factors and pro inflammatory cytokines into the joint. So that is fascinating to me. The products of this, as they say, may contribute to inflammatory and degenerative processes that underline joint diseases such as osteoarthritis and rheumatoid arthritis. I've never considered the synovial folds to be a, maybe not a primary, but a driver of that in any capacity. But it seems as though they might be and super, super interesting. Now let's talk about some synovial fold entrapment. That's what we deal with as chiropractors each and every day. So the previous hypothesis has been that abnormal joint movement may cause synovial folds to move from the normal position and become imprisoned or entrapped between the articular surfaces, causing pain and hypomobility. And that can have a reflex muscle spasm as well. And I don't think there's any. That's not news to us. As chiropractors we see that each and every day. Now, there also is entrapment and then there's X trapment, which is interesting. X trapment is when the synovial folds fail to re enter the joint cavity following movement which can buckle and cause again, reflex muscle spasm, can cause capsule issues. So entrapment is when the synovial fold is caught within the joint. Extrapment is when the synovial fold is caught outside of the joint. The when somebody's going through a motion. And again, fascinating. I've never thought about this in this much detail, but it makes a lot of sense. And this ties in, of course, if you take care of anybody that suffered and struggled with whiplash injuries in your practice. So there's a majority of evidence regarding the role of synovial folds in the generation neck pain and can become super injured during whiplash during a motor vehicle accident. That could be also like a slip and fall. Anytime that there's neck trauma, there's fast, you know, or this fast flexion and extension or hyper flexion and hyperextension. It's basically a whiplash injury. We associate it with motor vehicle accidents, but it can happen in sports. It can happen to slip and fall. Of course it can happen during those accidents, but that can play a huge role in injury or entrapment and extrapment related to the synovial folds. And as those synovial folds decrease over time as we age, I don't know. They don't go into it in this study. They. The real question is are they more likely to n trap or more likely to X trap? I think that's a fascinating question that can be answered in future studies, but this one that we reviewed today was from 2011. Again, I'll drop the link down in the show notes. To me, this is one of the most complete descriptions. I know we went fast through a lot of that terminology on this episode, but there's just so much good information relative to what we're doing. And I just think about. I know the synovial folds can take place across a variety of articular surfaces, but when we think about it in relative relative to the spine and the spinal column, they matter. They sit within those facet joints. And most of the time we are establishing motion in those facet joints. Of course, we're establishing motion throughout the spinal disc in the full functional spinal unit. But there's no question when I think initially of a chiropractic adjustment of spinal manipulation, spinal adjustment, however you want to define it. When I think of that I think the first thing I think of is what happens in the facet joints and the synovial folds are undoubtedly the key player in that. So hopefully you picked up some additional information around synovial folds. If you want to dig deeper again, please feel free to check out the study. And before we wrap up today, I want to say a few words about a couple pretty awesome companies out there and one of them is Power Step. They provide fantastic orthotics. I've talked about them on the show before. I'll talk about them again. I love the powerstep orthotics personally. My father has found a tremendous amount of relief using these and they're willing to give you, yes, you a listener, a listener of the Evidence Based Carburetor podcast, a free sample. You can check them out@pro.powerstep.com sample Again, that's pro.powerstep.com sample Head over there, let them hook you up with a free sample, see what's going on. 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So thank you so much for tuning in. Thank you. Have a fantastic week in practice and I will talk to you soon.

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