In this lecture, we're going to talk a bit about the path of physiology of pain. And the hope is that this background information will give you some things to think about that will help you better understand the utility of the pain protocols. And sequences that will describe later on in the week, and that you'll practice and learn throughout the course as we define or describe pain. We can talk about it as an unpleasant sensory and emotional experience that can be associated with actual or potential tissue damage. Pain is a highly individualized experience, and it's subjective in nature. So what that means, from a clinical standpoint, is that we don't have any type of a device or a machine that can give us objective data about the pain experience. There's no number or anything that registers, were interviewing patients and relying on what they're telling us that their pain is. And so that's what we would describe as a subjective finding. The characteristics of pain can morph and change over time, as do the treatment strategies. And so pain fits into one of three categories depending on how long it has persisted. And so let's take the example of an injury, a broken arm. So, if you break your arm, you have a very real tissue damage, you have bone and perhaps tendons or ligaments that could be damaged. Sometimes there may be damage to the skin or the exterior tissues as well. And you have very real pain that's associated with that tissue damage. So, right, as soon as you break your arm, that's the very acute phase as the arm begins to heal weeks later. And when we move into about the eight-week-long period, if the pain persists, we begin to label that as sub acute pain. Which means it's persisting a bit longer than we would expect the tissues have begun to heal and maybe function is starting to return to the injured area depending on the severity of the break. But the pain is persisting, so that means that the nerves are still sending some signals to the brain that there is a problem in that local area. But it's starting to last beyond the period of time that we would expect pain to accompany the injury. And then as it goes beyond that period of about eight weeks, if it persists for months beyond that. Then we would term that chronic pain that's lasting well beyond the period of healing and persisting and maybe not responding to the initial treatments. And so that's when treatment strategies begin to adapt and change. You say that pain is not a disorder or a disease, but rather a symptom of an underlying condition, like an injury of some type. And there are many different types of pain which will describe on the next slide. But I want to take a moment to acknowledge that pain is one of our nation's biggest challenges in healthcare right now. It costs our nation billions of dollars every year in terms of everything from health care costs to absenteeism and presenteeism and the workforce, disability. And then of course one could extrapolate that out even into the opioid epidemic and the costs associated with that. It's really sort of unquantifiable how large the problem can be and how much it can cost society. And so one of the important reasons that we consider acupressure and other integrated therapies as we talk about pain is. Because some of our major policymaking and regulatory bodies have come out and said we need other approaches to pain. A decade or two ago we began creating the opioid epidemic by the over prescription of opioid medications, and now we've really reversed course on that. And the prescribing of opioids as much tighter and much more scrutinized and used for much, much shorter windows of time. But we know that patients still have very real pain and needs strategies, and so we can take integrative therapies. And we can aim those to impact the pain experience, especially at very important points in time, such as when pain would be morphing from acute to sub acute or sub acute chronic. There is a time where we can really impact that pain experience and intervene before our patient becomes reliant on opioids for example. So the different types of pain I mentioned before, there's no susceptible, there's inflammatory neuropathic and then functional. If you are a clinician, you already know about these areas of pain. And if you are not a clinician, this isn't something that you'll be tested on in this course, and it's not something I expect you to memorize. But it is interesting to know that they exist in something to think about if you're a clinician, and you already have pain management as part of your practice. For the record though, acupressure can be useful for all of these types of pain. So, pain is, as I mentioned, a very common symptom, and it can be encountered in everyday life, certainly in the hospital setting and the clinic setting. But as I think of the broad range of students in this course, I think of the many applications of having a few pain sequences. That could be taught to and two Clientele or students in the school system and on and so on and so forth. There are many, many areas where understanding a few easy things that could be taught to a person to do on themselves. To impact, something like a headache or a stomachache could very much change the course of a person's day. So I hope that you will think about all the applications whether you're a clinician or working elsewhere or thinking of using this for self-care.