You know in the Michael in the window where all the people's are the video. There's a participant chat and then share screen record reaction Yeah, yeah, my thing is I managed to do it Yeah, do you see do you see my screen now? That's right. Yep. I do. I got you Okay, I guess you see the screen that the screen that I'm looking at it says send calm Laura at the top Yep. Yeah, great.  Okay. My name is Michael The name of the project is send calm or there's Yeah, the name of the project. Let's just Keep it simple. It's send calm and it's basically I think I can draw on here This is a send calm device That's what it looks like and If you can if you obviously many of us have used a raspberry pi before and there's the concept of hardware attached on top or HAT In short and the send calm device here is an H HAT for For a raspberry pi devices All right, so Going back then Going back then to my I don't think I can switch back and forth from cameras Maybe I think everyone knows what a raspberry pi looks like if you look in the I'm not sure if you can see that. Yeah. Yeah, the one you can see the camera. Yeah Yeah, so anyway, so if you can imagine This HAT device Being plugged on top of a raspberry pi that's kind of what happens. I unfortunately am not prepared to demonstrate this But I do have a series of pictures here to show the device So that's how we're going to do this announcement of the project and on another day. Hopefully if luther invites me back Then we'll do a more comprehensive Demonstration that may be more than 15 minutes will take a half hour or longer The one thing that's a bit surprising Is that some devices like this? What is this called? Forgot the name of this thing It's a eon Forgot the name so a raspberry pi hats do fit on other computing devices and this is what we'll probably be testing Going for this going forward. This is what a Send com panel looks like this is a bare pcb With four send com devices there. You can see on the back that there are no parts to Assemble on the back. There's just some gold contacts, which are test points Actually, it's upside down Gold contacts, which are test points and there's no otherwise no parts that go on the bottom layer of the pcb the top layer of the pcb if i get That's where all the parts go And if you can imagine, okay It plugs into the raspberry pi 40 pin connector on that side and once you populate this panel Then it begins to look like the device photographs, which i'm showing over here I can enlarge that so we take a look at the device self So this is a send com device What i do want to show is that there are two different formats. We're going to do um one see So there's we're going to call one the send com E d u and we're going to call one d e v So this is a d e v Because i'll make that a different color This is a d e v model Because it has a battery connector It has a usb circuit it has a External antenna sma connector a chip antenna It has a larger mcu And it has a secure element So there's a number of features which if you remove them you end up with a With a edu device, which is kind of a Uh a minimal device lacking all of these features and we're hoping to make these available Um to universities And some research institutions Right so um going back to the Going back to the overview here Once you plug that into a raspberry pi and we've been we've made it so that um so that raspberry pi uh cases Fit very well, so we want this to be self-contained It possibly in a weatherproof case because as we all know laura laura when Works really well outside in forests and natural environments. In fact What I was so happy to see in ben's presentation of the community Compost device is that I can imagine that the community compost device would work very well in picnic areas in public areas parks Places outside cities where actually there's no internet connectivity It might be a good use for a device like the like the uh the sencom that we're doing So it might be good to combine for example sencom with community Compost Device right this is just one of the applications of uh what we can do with sencom um Similar to the community compost. This is non-commercial sencom is a non-commercial project And it's a very small team And uh, we're just getting started in the distribution. So we'll probably be sending out dozens or hundreds of devices to Groups for example like uh nyu the new york university in shan shanghai um Hopefully I can get some devices out to a hacker space sg as well because I think there's a lot of enthusiastic people who like open Source hardware and open interfaces things like sub gigahertz low power long range devices Anyway, here's another photograph of the sencom device taken from a different angle And so at this point uh because I'm not prepared to demonstrate it I'll take questions and then we'll do a quick run over of the project. It's repository Uh the blog some information that's online But before we move away from the uh hardware itself Does anybody have questions about if it's for layer if fabrication is simple where to find the source any questions at all Before we do our next five to ten minute Uh a stretch and then I'll And I have a question. What is it? Was it the four? It I have seen a circuit board Okay, yeah this send com device once you plug it into a raspberry pi you can access it over the urt connector and Command it to send laura packets to a laura wan gateway So it can transmit Sensor collected data Basically any data we can transfer transmit a simple number if you wish To other send com devices to other laura devices and to laura wan gateways So what you saw before in ben's presentation for example using things speak As uh the collector of data You need a transmitter To send the data from the community composter To the things speak server somewhere in the world. There needs to be a transmitter either an ethernet transmitter or a wifi transmitter And if you're not internet connected it can be a laura wan transmitter Do you understand how this fits into the picture then because this laura wan transmitter? Which we called send com can collect the data from a community composter And send it to uh things speak over a laura wan Network does that answer your question? well, so i'm aware of the uh The mqtt for example and the esp 32 have laura integration on the chip. So so there's nothing more needed Would this just be the same thing or or how does it different from the esp with a laura? So i'm not aware of esp chips that have an integrated laura wan a laura transceiver That's something new to me Well, it's just the module right? It's a module. It's the size of a normally esp module Uh with the pins and then usb port and everything and has laura They cost about 30 dollars or something Yes, that's right. So i i'm going to rephrase your question And i'm going to say uh is the send com device the only um such Hat or module in the worst that in the world that allows uh a laura developer to transmit data over laura networks And the answer is no there are a lot of other similar hats modules shields and such devices and and at least one fits on uh esp developer kit And um can do the same exact thing that the send com does in fact If you uh bridge these two pins here Which are the uart connected connection? It's a rx and tx root transmit and you connect that to an esp And esp 32 whatever Then you end up with exactly what you're talking about Ah, that's another way to answer the question Any other questions before I Let me just paraphrase the the thing the utility of the thing you built here is that it's uh It's a a a uh physical box which could have a hard drive and it could be a server And it could run the mqtt and it could be the gateway for the network for for uh for other things Where maybe cheaper devices having sensors Is that one way of of using this thing? Yeah, that is one way of using it is to combine this on an esp device Or we've made it to fit very nicely with our asbury pie But it can be used with a bbc micro bit or an arduino or any number of devices that can that can communicate over serial For example rs 232 or uart connectors That's how the esp 32 developer kits can uh use laura and laura when devices over their serial connector So that is one way to think of it. Do you have a price point of this board with the components? What does it cost to assemble? Okay, yeah, uh, so let me then I I need to go to the next So for the advantage of laura compared to ethanette et cetera or the Or the sick fox or whatever network is that this laura you can have a connection point to point Or mesh, which is you don't need a license, right? You don't need to To pay anyone to To laura device can talk to each other without any Any license to pay, right? It's you create your own laura thing, right? That's right brahiem. Uh so so from that from that point of view is that Uh, if we look at the case of singapore is laura already, um, validated in singapore and everything else, right? Well, I don't know that much about singapore I know that almost all well-developed areas in the world and the singapore is obviously included in this Have uh airwaves licensing Regulation, you know, there's you're allowed to Start a wi-fi access point because this is an ism band of 2.4 gigahertz ism stands for instrumentation and medical Instruments and science airwaves. So a person who buys an uh an access point on 2.4 gigahertz doesn't need to pay a license fee It's the same thing with laura when laura when is using in many parts of the world approximately 900 megahertz This is unlicensed airwaves The license fees you were talking about before with sick fox is a different thing. That's I I think Starting to talk about that we will get confused partially because i'm not so knowledgeable in sick fox Just that uh laura the laura similarities. The laura is uh in asia is uh 433 Why in europe is uh, let's say eight six eight six eight. I just read from the web the So it means that the chip that you have on that board Is also compatible everywhere. All these laura chip actually Have a kind of configuration that will us will allow us to use them easily in singapore Yes, the answer to the question is if this device is able to transmit laura modulated radio at all of these different uh worldwide Frequencies the answer is yes. It's user configurable and it's very easy It makes it easy for you It basically asks you at the very beginning of its menu Which area are you in and is this the frequency that you want? So it's kind of built into all the different layers application layer that the user sees on the screen The modulation layer that the transceiver is modulating at Those frequencies are all part of this And brahimi you're right that most of asia does Typically use 433 for the frequency. This is a problem for us When we have different frequencies such as 915 megahertz, which is north america Uh 868 which is eu All of these frequencies you can see they're Close to 900 megahertz. So these type of antennas which are made for 900 megahertz transmission when you start to When you start to tell it to transmit at 400 megahertz transmission You can imagine it doesn't work very well And that's the limitation that you're also asking about will these devices successfully Work in asian environments which typically use 433 megahertz. I think they won't but I think So when you buy a laura wind device, I did this for an esp 32 once it came from asia to my door in eu And it I immediately could tell that the antenna resonated at 400 megahertz It would work But only if I was communicating with other devices in the same room because the You know, it still works, but you will you will have terrible range. Does that make sense brahimi? Yeah, okay. I just want to to check because uh You know if you push such a device Let's say in singapore for university school, etc We should be quite sure that you know things are working properly also that the i'm not a Radio i matter like some of our colleague who are part of the The hacker web but some of our colleague have friends. I would say colleague You know, uh, no more about the regulation. I think in singapore Uh, we have to be very careful. But you know, what do we emit at what frequency? Uh, the rules are a bit more strict than uh elsewhere Yeah, well, I think there's lots of us I'm sure when you when you present your you know, the tools the github the api We can we can you know see the the kind of uh compatibility later with with asia Uh potential customers for us to you know, we we can buy some of those boards Especially that a lot of us have a raspberry pi's around so actually it'd be nice to create a mesh Yeah, exactly. There's there's a lot of uses for laura and laura way in technology like uh Like catastrophes when the internet is not working because of whatever emp In any case, um before we stop talking about frequencies I'm not sure which countries in asia are um Are usually Are commonly using 430 megahertz, but only out of practice I believe that china for example does have a 900 megahertz band That is licensed or not, you know unlicensed and you can use it I'm not so clear about that yet for obvious reasons. We're mostly focusing on the approximately 900 megahertz bands It's actually impossible without making two different Uh, uh circuit Circuits to serve these two frequencies So it's a problem that we have identified brahiem Just like you have mentioned and we're working on it But we don't know how to solve it in the best way any other questions. Do you have a question luther? Yeah, so no, i'm good. I think uh In our zoom chat that uh, uh, a few years ago, uh deep require permit for laura frequencies Yeah Yeah, so it it's it's certainly not so easy to control Our design to work in every city of the world to understand. They're changing legal jurisdictions One year one is going to switch from 868 to 900 the next year we 915 other regions will switch at 433 That's a problem that we definitely will always have just like all of the other manufacturers All right, so i'm going to switch to to my browser now to explain where to get more information First, let's take a look at if you're not so knowledgeable at with laura wan in particular It's rather easy to find sites just by simply searching for laura and laura wan Here's another one activity has a lot of general purpose information and documents laura wan. What is it? And you can take a look at here key benefits, etc. Then there is a site There's a wikipedia site This is a bit difficult to Get my screen to anyway, all right, so um, this is the wikipedia site for Um laura and laura wan. I'll just mention one one thing to take to understand laura is the Modulation controlled by a company called Semtech it's partially open source, but not all of it is laura wan is the specification. I believe it's fully open source Which uh, is no longer this is not peer-to-peer as brachy, but no I can't remember who asked about peer-to-peer But when two devices communicate with each other without any gateway in between then you are not doing laura wan You are doing laura instead between those two devices. So that's one important distinction and go to the next one is Here is a things network another important site to look at things network. This is kind of similar to To ben's things speak, but this is simply a transport. This is just about communication. This is not about collecting and uh displaying data So these are the type of sites that you might want to look at if you're trying to get a general Impression of what laura is and what it isn't and if you want a specific impression about the project the sencom project Is being hosted by the company called your opa lab devices Oh, uh, and I believe this is german. I apologize How can I quickly change the Here maybe yeah And so you can explore the different Projects there's very few at this time. There's a few Projects which are not open source And this one is open source. So this is a democratic send com project And these are this is basically where we do our work and commit our Changes to This is jip dot your opa lab dot com for all of those people who would like to download a key cad project for example, I'll just Show you through the different areas you can look at the firmware there. Let's take a look at what applications we're We're interested in in showing for the first time Here's a peer-to-peer application. You need two sent com devices to have this peer-to-peer application work um, a laura wan ot a or on the over the air Registration style application is here. Here's just a hello world. This is all the firmware Software we're not producing software software is what would run in a in a web interface or a mobile phone or a macintosh What do they call it? cobalt Carbon all of this stuff is software And this project does not include requirements for any software at all So the way to use these applications, for example in the firmware In the firmware directory is by connecting your raspberry pi and accessing it over the serial interface This is what's going to Interest most people is the hardware Sub directory. This is where for example I'm gonna have to clean this up a bit There's too many files, but this is where you have your ds com profile here. This is a project for key cad you have our master Schematic which is a sch file And you have some for example, here's the master layout The key cad dot pcb Now because if if I click on some of these files, then all you end up with is difficult to read raw text This is will take a little bit to load. This is what you see. It's a very long file It's not so useful. You can kind of understand a little bit about this here But you can't see any any traces or graphics So if you're interested in the hardware Then there is a Michael another three more minutes it comes in a time, but you can you know hang out later Right. Okay. I will Finish this up quickly then. Why is this now? I'll just move on. I guess I was hoping to It's hoping to show the pdf If I lost my connection what's happening here All right, so this is a different website. It's me mainly the blog. This is new zero the lab.com and most of the status reporting Is about this project democratic sun com so you can see there's about 10 entries which are all about this Project, this is another place to get your information. This is news dot the lab dot com An example of how this looks to the user Is here and now I think by him you can more fully understand When you're choosing the band And it doesn't show the screen where you choose the frequency and band unfortunately. I thought it would so I'm sorry about that um, the last Is okay. This is doc which is not well developed. I don't have the documents there yet And we're also developing a workshop like a training or educational environment for the advice here So these are kind of the project specific areas that people can try to look at if they're interested in more information about The device this one which seems to have crashed Interesting, okay, so I think I'm done speaking about the project. This was an announcement of the democratic cent com And I didn't do any demonstrations, but I hope that if there is time on another day on another Meeting that I will be able to do to demonstrate the device. Are there any questions about the project? Yeah, I think possibly has a question possibly was possibly you're there Uh, yes, uh, no, actually I was just reminding, uh, I think Someone asked about the price just now the price point I'm sorry. Yeah We can we didn't so so what So it is in this repository, which seems to Seems I don't know why it's not responding So the the bill of materials. Okay, here it is. Let's try one more time. I'll try to do this within a minute That's going very slow Maybe there's so many people that are interested in the project They're all bombarding the Okay, here it is. So we have the Bill of materials here And if you take a look, uh, there is no pdf. Let's go back to the pdf of variants the print here And the bill of materials is a pdf file and this is kind of the nice representation. It shows you The bill of materials that will make this larger say about 200 percent And you can see the different parts, which is the traditional bill of materials the The design designators at the very bottom, uh, you can see that there's 63 unique parts with 110 parts Total quantity and at the very right hand side, you can see some of the Costs so for a person who buys exactly one Of one inductor One antenna connector one resistor for all of these different parts Then you end up with the highest cost of 48 euros total net cost For a person who buys enough to make 1000 devices and obviously the total net cost goes way down So does this answer the question of what the parts cost of this device is? Or is there another question about the cost like assembly? Uh, is there any question about costs and prices? Yeah, what's what's the estimate like a full board like that, uh, which which can sit on a Raspberry Pi? How much are we looking at? Right, if you make this yourself, which means there is no assembly cost because you're using a A tweezers to assemble it by yourself and you pay for all of the parts Then the cost is about 50 euros If you make several at the same time or you don't need to buy all of the All of the parts because you have some in your lab already and obviously the price goes down If a person like probably I'm not sure we're going to commercialize this if we do and we will obviously Uh, we will obviously, uh, produce 100 to 1000 of these devices at once and that price will come down to I assume Uh, it will it would have cost us probably 20 euros in parts and another 10 or 15 euros in assembly costs The reason that assembly is so expensive fozly is because we have some BGA in there We have a BGA Half millimeter pin to pin pitch with 88 balls, which is kind of challenging But that's kind of a rundown of the costs. Does that make sense to you? Or do you think your cost if you were making this device fozly in singapore would it be higher or lower? No idea That's a clear answer I guess if if all the files are available on your github someone load it into a key card key card has a Some sort of plug-in to actually talk to some Um, whatever gb gb pcb or whatever in china and then you know You know, someone could assess how much it actually cost Uh, you know to really get the board being done Sold it and tested somehow You know, so I guess we could estimate Uh, but somehow like clearly it would be less than 50 euro because That would be like, you know us soldering a bga, etc. So First of all, yeah, we sold bg. I think we need some proper equipment I would like to know The choice of those of those components Compared to alternatives because there are some hat Laura hats for For raspberry pi already if I google a bit I find two So what would be the advantage to to use? That you know your your board versus another one which is already on seed Whatever all these famous Like like website. Do you have like a you know, like a like a specific aspect that that that would convince people to say Oh, I want this one More than others Let's say the chip the chip is an s6 When I read laura, they all say s6 Uh 12 78 so I assume that all all of these boards are using the same chips um Um, I'm not sure if the guy is online, but there's there's someone I follow on twitter Who's really into laura in singapore? So I think this is the person we could you know try to make you in contact Uh, I don't know the name darling Can you get me my phone? My mobile phone, please Uh, I follow one guy on twitter You know and he's very laura. I read all these all these uh, yeah. Yeah loop. Yeah loop check. Yeah. Yeah So that's someone say on the chat It's okay. It's okay It's okay. It's okay. Uh, yeah loop loop Chinese someone in singapore who's really into uh loop chen so really oh, yeah No, it's not online tonight, but uh, it's someone who's really into laura Something you see someone really, uh You know if you if you try to push this in singapore or have some kind of uh, that that would be nice to Even create a workshop or something like that that that should uh, you know, how I think get plugged You know it convinced people to uh, not not everybody's uh I mean I for one don't sold the surface mount stuff.  So that's one of the the great advantage of it. But in terms of Of range in turn of of uh, of bandwidth Latency these are I think parameters that people should be uh, uh aware when when they step into the laura Ecosystem and and and world in a sense, um Because I would assume that this has less bandwidth than wi-fi And in terms of range, it's actually, you know, better than wi-fi, I guess, uh, if I'm not wrong Brazil Yeah, so I have a question Different from hi. I'm gp here. I have a question. So, uh, slightly different from what The question may ask. Okay. I've briefly just went in and take a look that laura people do Joe positioning with laura. So, um, I would like to hear from you if You have any experience on this that you would like to share. Thank you Sure gp, but I I don't understand the specific question. I would like to share information for you Joe, what is the question? Joe positioning that means I using laura to actually, uh, to to Let you know what this device are where it is, uh, it's located Geo positioning, you know, now I understand the question. So this device the sencom does not have, um Does not have a receiver a gps receiver It does not have that doesn't have, uh, things that are useful for geo positioning So what you would need to do is combine this With, uh, whatever you use for geo positioning What we're not trying to solve are specific problems like forestry altitude weather balloons Heating tsunami detection, we're not really trying to focus on geo positioning or, uh, combining to with microwave links or We're trying to make this available for Institutions like universities who then take the device And discover its specifications. They put it to use in their legal environments like 900 megahertz and they develop, uh, work Work groups now they develop, um The pipes Track classes and so on using this hardware So we will definitely create a user manual and a few things like that But we don't have the resources to explore individual applications like geo positioning But maybe you gp lee, uh, tphe would, uh, liked if you're close to the, uh, Singapore hacker space You might be able to find one there I'm hoping to make them available there And then you could do the work that is meaningful to you if you like an application like geo positioning Maybe you could combine the send com device with whatever geo positioning tools that you're already using Do you think that's realistic? Yeah, I think so because My initial thought is that the signal itself may May help in, uh, fighting out the location device So it's actually it is actually it's based on the the gps signal itself instead of the six foot signal Yeah, but I I don't think that's the case with laura went so, uh, triangulation of wi-fi of 2.4 gigahertz Um signals has been attempted and works well sometimes bluetooth is known as well to allow for some triangulation Um because usually you have a constant wave So your modulated signal is going forever Unfortunately with laura when we have what we call a chirp protocol So we have a a wave here. We have a piece of a scion wave there a new one there You know and then 10 seconds go by And then we have another piece these are chirps right and Because we're not transmitting all the time like a continuous wave It makes triangulation of these devices extremely difficult Does that make sense? So i'm not sure if laura when itself can be used for geo positioning Then this is why so many laura when transceivers are accompanied with the gps transceiver that is on the same pcb If any of you have a laura when transceiver at home for esp or whatever It's really common to see a gps transceiver located next to that for exactly this application Understand, okay. Thank you Any other questions or shall we go back to luther? Yeah, um, I think uh, you know, I I think it's a very very interesting discussion I think for both talks, you know, there's a lot of audience participation And I we definitely have gone uh gone past that look at the time, but you know, I think um Uh, let's say I'll let you guys have to actually end the session because we actually had When I overstretched quite a little bit, but you know, that's a short, you know, the zoom the zoom The zoom session you will still be in place. You can hang out.  You want to make it, you know, as you know realistic as a physical meetup as close to that as possible Right and so thank you very much everyone for your time and for your fantastic discussions and you know, if you have not already Our oh, hi. Oh, that's you. Hi. I see I'm not in the camera And uh, yeah, if you have not joined our telegram or our discord group Please, you know, feel free to actually join a group and definitely also our physical So, thank you everyone. Yeah, please hang out and chill and I think um For anybody who has questions for michael, please carry on. Yeah. Thank you Thank you Great you good meet up nice. Thank you. Okay. Bye. Bye So far michael, uh Try to register to the to our Uh discord, maybe server hacker Yeah We can We can yeah, create some laura and mash in singapore Yeah, yeah Yeah, I already brahima i'm already on the telegram channel and I believe discord is just a bridge So there's no need to register there as well on the telegram thing. Okay If you can share your your your slides or your the links on the telegram group we can repost on facebook and stuff Okay Right This you you want you want this Uh Slide this. Okay. Sure. I think I can do that. It's a good idea. I didn't think of that firstly, but it's a good idea Put the image so we can advertise it through through our web or facebook Yeah, yeah, I will do it Yeah, but um, so actually michael just to follow on your process now you were are you looking for uh, what's this called distribution channels for this like, you know people who are who are like seed or I don't know. Uh, I brought up citron in the telegram chat Is that yeah fuzzly, uh, I I Because we're doing so much work to produce the devices now and we need to serve universities and research institutes Uh first then that's why we haven't Focused or were made a distribution plan for commercial environments like seed like 12 geeks And so on but the answer to your question Are we interested in distribution? In commercial environments is definitely yes What I would like say in two three months Is to have At least I'll reach out to say 10 distributors And I'm hopeful that at least three maybe even four or five of them Request a package of devices Minimum order quantity let's say 50 Let's say a couple of them will request 200 I can produce up to a thousand And they receive them put them up for sale in 12 geeks. And that's my Very overview level generic, uh hope for the commercialization. Does that make sense? Do you think that's practical? Um, yeah, of course So, I mean that's uh, yeah, I just wanted you to put it out there and I don't know anyone else who is on this chat or so maybe could think about it Yeah, so I think uh, I'm not was sharing that, you know, there's false easier coming up So I think that's another I'm not sure that Michael you're aware of false Asia It's a conference open source conference in Asia Yeah, so I think that's uh Yeah, so I think there's another possible platform for you to actually, you know, create publicity and more awareness Luther, do you know when the next fast Asia is taking place? I think very soon much is it much much. I think, uh, what's his name must Roller Roller Is it rolling in here rolling was in here just now he was in here. Yeah, but he left Yeah, do you know if the what's called called for papers are closed really? I think it's on facebook you send a reminder Okay. Yeah, maybe we can send Michael the link. Yeah I that's nice fazley, but I know Hong Fook very well and mario as well. I think they're So, um, I'm very well in touch with them. In fact, one of the the ideas we've had Uh is to make a send-com format device for not only raspberry pi but for their pocket science lab of psl device Which they are Distributing for example, I think on 12 geeks. You can buy the pocket science lab And it has gpio connectors and the uart connector that would be very easy to make a send-com device for that So there's all kinds of reasons to get involved with false asia and to try to you bring these two projects together Right. In fact, I've talked to mario about this. So the very first Mentions have been made but it's good to know if it's march, you know, if it's coming up false asia again Maybe I should hurry up Right. Yeah. Yeah, maybe you can do your full display there As a follow-up. Yeah, not not just the 20 people in heck where Yeah, well somebody I can't remember if it was yubraheem or somebody mentioned there is a person very, uh in-depth Involved in laura-wan in singapore and you wanted to have me contact them or the other way around So I wrote my name on the telegram channel now That's one of the ways that you can pass my information onto them. We really appreciate if you did that I don't know this person. Uh, let me get my phone. I really like singapore Yeah Oh I have a question for you. Are there any university environments higher education style Institutions in singapore that I might be able to meet a professor In order to send them a package of 20 30 50 devices and they use them in a classroom environment Can anybody give me a couple names of universities? Well, there's only like three universities in singapore Yeah, so I I mean there's NUS and NTU. Uh, yeah, you can approach them um Yeah, but we'll find out the exact Um professors who you can get in touch with Which are the school will be good? Yeah, NUS and NTU I'm not on telegram Hacker hacker where telegram is is kind of work now Um So, yeah, I will add myself and then I'll send those link. Uh for cegia It's uh 13 to 21st of march to 2021 So I guess it's gonna be online over over a few days Uh, uh, yeah to be honest because it's going to be online. I think it's going to be a massive amount of of people Painting it because they don't have to be physically Yeah, it was a video Michael a one question for you does Um, do all boards with laura use the same chip or do they have many different manufacturers? I know the same tech and Is it other than any other chips produces? Yeah, if you ask that question one year ago I would have said there is only semtech manufactured laura chips on the market Um, but even that question You have the sx 1276 which is only useful for one channel So this is what most laura nodes are built on the semtech sx 1276 If you have a gateway it needs to listen and transmit on eight to 16 channels at once So it's a different chip, but it's also from semtech. Semtech is kind of the monopoly figure in laura land However, since 2020 in fact, I think maybe 2021 Is the first year that st micro Um is creating. Let's see if I get this right. It's called the st m 32 w l e 5 And this Contains zero semtech technology It's all st. This is a really really hot device Um for a number of reasons. I mean There's presentations that go on for hours about the device because it's packed with so many interesting features Stm 32 w l e 5 is one example of a non semtech laura modulation transceiver. It's combined with a mcu The one that we're using is also a very new chip. It's called the uh Running out of space. It's called the micro chip sam r 34 And as I tried to draw before this is laura Plus mcu. This is So this is semtech as x 12 76 plus cortex Zero That's one long-winded answer to your question fosley. Okay. Well, that's good to know that it's expanding yeah, so Funny funny you mentioned Sd microelectronics because some guy just walked in my office this afternoon from sd microelectronics Unannounced and he's like, oh, I want to buy a What do you want to buy? Oh some some haters for his aduino Yeah, so I don't know will you like to get in touch with sd microelectronics? Well, sd microelectronics is sponsoring some of our parts on the parts list So we're already in touch with them. But if you think that the office in singapore Has interest in this project in order to move it or migrate from microchip to st for example Then yeah, we could consider these types of things have a new version I'm not sure if you said st micro or semtech. No, I'm getting mixed up sd micro sd micro Yeah, right. We actually have no offering that integrates st micro technology yet But we have received a load of chips from them and the next there will be at least a design I'm not sure when that will appear because it takes so long to test these things That will include st micro Technology feel free to tell your contact that and you know if they want to know what's taking so long Or if we need extra help or if they want to learn about laura wan in general and all of these things are are You know what interests us as well? Okay uh One more question. Do you know of any like successful commercial projects which are built on laura already right now? um I mean, how can I answer that question? I I do know of one in england. It's called low pi they're kind of building a laura wan stack in python and making it easy for users to hook up their devices to laura wan by buying a low pi transceiver So They're possibly they're quite a lot of these. Um, they're they're actually quite a lot of such projects that are either gateways or modes or something similar And I can't really list them all there's just way too many and i'm not familiar with them because i'm working on sencom And not on low pi Yeah, no, no as in my question is more on on the application level not on the network level Uh, that's another good question. So, uh, what type of applications are suitable? For example, uh transmitting the The uh volume of a trash can is an application which is a real world problem and has been solved At least one or two companies. None of these are doing it in an open source manner So you can't download archives of key CAD design but um when a trash can Will you know like a smart trash can fills up? Then you want to know if it's full or not and these trash cans are put in all kinds of places in the world Lots of these are in you know on ships in the middle of the atlantic. You have a trash can you still want to know if it's full or not That's when you use non-internet technology and laura wan is a great application Level transport for this type of application. That's why I mentioned that the community compost Project could possibly make use of a send-com like we could somehow Unify the projects is just kind of a thinking out loud situation. I wonder if ben is still there Does ben have an answer to the question? partially that fosley just made such as when the Community compost fills up and it's in a for example a public area like a forest So it has no internet connectivity. How does it send its data to the thingspeak server? All right, is it going to use laura wan or something else six fox maybe or lte? What is it called? I assume it's just wi-fi But there is in there isn't a wi-fi in forests because in uh I think those I mean he's uh He's whatever box is actually close to the cc or something. So he's probably tapping into the wi-fi Yeah, I don't think in singapore someone is paying A six fox for something like this unless there's a lot of money So I think it's the prototype proof of concept and then you tap into the wi-fi close to the the community center and and then it just This project is not not already But I think actually ben actually gave a talk about laura before he did a project on it So probably he could uh integrate it I think at some point whatever you want to talk to the cloud you need some internet and somewhere it has to be a private or A box somewhere that someone has to pair and so the cost is there But I would say the no because all of us have uh, I mean we have We have esp you know in every box everywhere. Yeah So everywhere now. Yeah, it's like, you know, uh, we're buying another raspberry pi picot. Yeah Have you got the name? No, no, uh, but I mean It would be nice to experiment with you know having two at least Uh, I'm interested to know the the stack on the raspberry pi. Is it already fully developed? uh up to a point where we can Link everything with the with any c program or python all the binding is already already there Uh, yeah, but you have the wrong perspective. It's not very easy to understand but this mcu Right here. It's actually able to work without a raspberry pi So all of the firmware that you develop using a c compiler downloading the source code It's going directly to the mcu. It's not going to run on a laurel and stack on the raspberry pi That's another difference The mcu is talking to a raspberry pi through the spi interface, right? Through the serial interface rx and tx Yeah, I think it's just to send data You are So on the raspberry pi, uh Okay, okay. Okay, so it's like a like a basic modem Okay, like the like the modem that's right And that's what allows us to abstract this software layer or the stack as you say from arduino Which would require obviously a completely different stack than raspberry pi ESP is tencelica, but the next esp will use risk You see so if we if we were Doing the software on the host it would require us to to maintain a whole bunch Maybe even a dozen of different architectures and so on and by doing it this way by running everything on the mcu We can just attach a battery to this device brain. We don't even have a host. There is no esp 32 There's no raspberry pi which is out of battery on here And it works and it can be integrated into a smart trash can or a lamp post Or all of these different devices out in the open which have no internet connectivity But the information still goes through the uat. So after the uats you have to deal with it one one other It doesn't need to go through the uart right you can gather data directly on this board It has an als an ambient light sensor a thermistor so you can generate data on the board And transmit it over mora when and there is absolutely no host that controls it or gives it data Because all of the data is generated on the board. That's just one of the use cases Most people Data on their esp 32 or their raspberry pi They will send in numbers or colors or encoded information and that's what they want to transmit That's the standard use case, but it's not mandatory. This device can be standalone You can connect a battery to it and it works without any host I Michael I see like there's a usv port or something on the bottom right hand corner of it. Um, maybe not this uh spring Let's see. Yes. I think this is the best picture where you show where it shows the usv. Is that there's a power port or? um, it yes, it um, it It can be used to power the device It can also transmit data to the vice so you can flash the for these are all advanced features which we have not implemented yet so if Like I mentioned before there are two versions of the device. I think it's I wrote it somewhere else, but there is the edu which has no usb port and there's a dev This has all of the features All right, so this has this has the Uh usb it has the battery. It has a larger mcu. It has a sma connector. It comes with the antenna it has a secure element And if we commercialize the dev model for example at 12 geeks or uh, there's a pocket science lab style commercialization Then we will uh implement enough logic into the usb port to at least allow it to power the device and communicate Like the uart serial connector does Does that answer your question? Yep. Yep. Yes Regarding power, uh this battery here This actually um does not power the entire device It only backs up The the configuration and the data on the device so that if you disconnect it from a raspberry pi that your data is still Is not erased All right, and the other power options are through the the raspberry pi connector Um, and then there are some test points as well, which are useful for powering the device And we don't really have a feature a hardware feature like a lithium Battery which you can recharge. These are circuits which could could go on the back of the board, but we have to we have to kind of Stop implementing some time and and turn to maintenance and support So we have not developed any rechargeable lithium battery pack Yeah For geo positioning for example the thing the application that gpe is so interested in would be very very useful To have a battery pack on there And we're all hackers. So if you go to 12 to singapore sg hacker space As soon as it opens again, then there's really easy ways to hack one of these devices to become Portable and mobile and hang it off of weather balloon or put it on your bicycle So that's what one reason that all of the parts are very large so that you have the option to solder onto them and to attach new and Power supplies, you know power energy harvesting whatever you need. You can probably do it Okay Well, okay. I think I have to go off. So uh, thanks michael Uh, if anyone Uh, it's actually bedtime Yeah, I have to put my kids to sleep. I actually have another meeting after this So nice to see you again. Um, hope to see you. Um, maybe next Hackware you can join Yeah, or maybe at a false agent Yeah, that's my plan. I'll see you. I'll see you all. Thanks a lot for coming


We welcome you on this Sunday morning for the Indian Radiologist Journal Club. This is something which we were doing almost every month last year, where we used to take one article with relevant topic. And one of our experts used to review that article for the next one hour or so, to get into the details of those articles, include their experience into it and also show a few cases relevant about it. So continuing the same thing we have started the Journal Club this year as well and we'll have it every Sunday morning, which will be the first Sunday of every month and morning 10 to 11 a.m. And for this we have with us Dr. Chathali Parik and the article she is going to take is post-aromideal corner of the neglected corner. Dr. Chathali is a well-known speaker on, especially on Indian Radiologist Forum. Her videos are the ones which are like and subscribe the most. So she is one of the most popular speakers and we have been learning MSK with her. She is consultant radiologist for Pulse Chain of Diagnostic Centers and she has done her fellowship in Musculoskeletal Diagnostic and Intervention Radiology at Innovation Imaging Mumbai. She has received Dr. Aran Goyal Ghul Medal for best paper presentation on MSK interventions and she was also selected as one of the best speaker at RADAC speaker competition of radiology review course. So we welcome you Dr. Chathali and over to you. Thank you so much Dr. Mithusha for this wonderful introduction. Good morning to all of you. I hope my screen is visible. Yes. At the outset I would like to first thank the Indian Radiologist team and Dr. Mithusha for this wonderful invitation. I know this is a bright Sunday morning and most of you would be having better plans for the Sunday morning. So I would like to I will try to keep this session short and not extended too much. Without wasting any time, let's begin with the session which is the journal that we're going to discuss is predominantly concentrating on the posterior medial corner. Now, why I have mentioned it as a less discussed corner. First of all, we do not report a lot about the corners in our day to day routine life for the knee joint. So you've got a posterior lateral and a posterior medial corner. However, in recent times, there has been awareness of the posterior lateral corner and we are putting it in our reports which is helping the orthobots. But posterior medial corner is again something which we are not looking at all in our day to day practice that corner is also important for the orthobots for the stability of the knee. So we are going to today discuss about this corner. The article which we are predominantly concentrating on is the posterior medial corner of the knee, the neglected corner, which has been published in Radiographics in 2015 and written by Ryan Lindquist and Ital. Another similar article that we have is the posterior lateral and posterior medial corner injuries of the knee, which was published in MRI clinics of North America in 2014 and written by Daniel Gager and Ital. The reason I'm not predominantly or primarily discussing this article is because it covers both posterior lateral and posterior medial corner. So anyone who's interested in understanding both of these corners from the basics, this is a really good article. But for today, we are only concentrating on posterior medial corner of the knee. So posterior medial corner, before I start, what I'm going to do is first I'll be explaining the anatomy on the slides. Then I will be switching over to a normal anatomy scan. Then we will discuss about the posterior medial corner injuries again on the PPT slide. And then again, I'll switch back to the abnormal scan. So I'll be switching my screen between the PPT slide and the DICOM viewer so that we can look at the scans as well. So posterior medial corner has got five components. So we've got semi-membranosis and its expansions, posterior oblique ligament or the POL, oblique poplite ligament or the OPL, posterior medial joint capsule. And the fifth component is varying between the articles. So there is still a bit of research that has been going on about the components of the posterior medial corner. And the fifth component, some articles mentioned posterior horn of the medial meniscus, whereas some articles mentioned menisco tibial component of deep fibres of medial collateral ligament. Now, what do I mean by deep fibres of medial collateral ligament and what is the menisco tibial component? I'm just discussing this part of, sorry. So these are the four major components which we will be looking at. And since we won't be discussing medial collateral ligament too much later, so I might as well just show it to over here. So we all know that medial collateral ligament. So we've always been looking at this outer structure of the medial collateral ligament, which we very well see on the coronal images of MRI scan. The outer long linear structure, which is seen on a single image, those are actually the superficial fibres of medial collateral ligament. You also have the deeper fibres of medial collateral ligament, which is relatively shorter ligament. It has got two components. So it goes from the medial femur up to the medial meniscus, which is the menisco femoral component. And then it goes from the medial meniscus to the medial aspect of tibia, which is the menisco tibial component. So there is a deeper fiber of medial collateral ligament besides the routine superficial fibres of medial collateral ligament whose injuries we are reporting in day-to-day life. Now it has been said that the menisco tibial component of the deep fibres of medial collateral ligament is also one of the component of posterior medial corner. However, some article suggests that it is not a part of the posterior medial corner, but it is just one of the structures that supports the posterior medial corner. Okay, so what exactly is posterior medial corner to begin with? All the area that is extending posterior to the, so along the posterior margin of medial collateral ligament and the medial margin of posterior cruciate ligament. So the area that is spanning between these two margins is your posterior medial corner. Anteriorly, it goes up to the posterior medial menisco-capsular junction or the posterior horn of medial meniscus. Posteriorly, it goes up to the semi-membrinosus tendon. So from the posterior margin of MCL, along the posterior menisco-capsular junction or the posterior horn of medial menisco-caps, medially up to the medial margin of posterior cruciate ligament and posteriorly involving the semi-membrinosus tendon. So this entire area is my posterior medial corner. Now, again, we look at the diagrammatic image and along with that an axial PD image to understand the anatomy well. So here you can see that these are my superficial, so this is an axial image, an axial diagrammatic image. You can see the nice large meniscus, which is the medial meniscus. And here you can see that this is my medial collateral ligament. So these are actually nothing but the superficial fibres of medial collateral ligament. Just posterior to the superficial fibres of medial collateral ligament, you have your one component which is the posterior oblique ligament or the POL. Now, this POL goes posteriorly and this forms the posterior medial menisco-capsular junction. Further on, when you extend the posterior medial menisco-capsular junction laterally, what you get is your oblique poplite ligament. Behind your posterior medial capsule, what you have is your semi-membrinosus tendon. So these are the structures of your posterior medial corner. So coming on to the PD image, now you can see there is a nice black line that is going, sorry. So you can see there is a nice black line that is going over here. The anterior half of the black line is actually your superficial medial collateral ligament. And the posterior half of the black line is what is the posterior oblique ligament. So this is actually almost at the level of knee joint line where we are looking at the lower most part of the femoral contile. And so this is my posterior oblique ligament. As it goes inferiorly, it will join with the posterior medial capsule of the joint. And here further, there is a lateral expansion that goes from the capsule. This is your oblique poplite ligament. So this is my oblique poplite ligament. This is my posterior oblique ligament.  Okay? So this is MCL. Now, here what you see, everybody is aware where to look for the Baker cyst. So what you have is the medial gastrocnemius tendon. And just anterior to it, this is the semi-membranous tendon. And this is where your Baker cyst is actually going to come out, right? So semi-membranous tendon is over here. And what you see, this is your posterior medial capsule. So once again, revising, semi-membranous tendon, posterior oblique ligament. So this is your POL. I'm really sorry. I'm very bad at this. This is my OPL. That is oblique poplite ligament. And this is my posterior medial capsule. So these are the major components of the, these are the major components of the posterior medial corner. And along with that, you can appreciate very well on the diagrammatic representation as well. Now, as you go one step inferior, you can see that this posterior oblique ligament is now actually merging with the posterior medial capsule. Okay? So this is how the posterior oblique ligament will merge with the capsule. This is the semi-membranous tendon. From the posterior medial capsule and the semi-membranous tendon, the structure that will arise is the oblique poplite ligament. Now, semi-membranous tendon itself has got five different insertions or five arms. What are those arms? The first one and the most important one is the direct or the principal arm, which attaches to the tubercle on the posterior medial tibial condy or in the groove just above the tubercle. Next, what you have is the anterior arm. Next is the capsular arm, inferior arm, and the oblique poplite ligament expansion. Now, of these, it is difficult to differentiate the direct arm from the anterior arm on MR images. Next, what we're going to look at is the posterior oblique ligament. As I've already mentioned, it is just posterior to the MCL origin arising from the adductor tubercle of femur. There are some variations in the origin of the POL, but it is more or less close to the adductor tubercle. It runs posterior inferiorly and attaches to the posterior medial capsule and the posterior horn of medial meniscus, just as we've shown before. So, again, just another diagrammatic presentation so that you can understand the POL very nicely. So, here, this is my MCL in black and this yellow dotted line, what you see, so this yellow dotted line is my POL. You can see the black dotted line is actually nothing but the capsule of the joint and the POL will eventually go and merge with the capsule of the joint on the posterior medial aspect, right? So, this is how it is going to go and merge with the capsule over here. And what you see over here, this is my semi-membranosis tendon. OPL arises from the capsular arm. So, I've already told you it arises from the semi-membranosis. So, it actually arises from the capsule or arm of the semi-membranosis tendon and its lateral expansion. It goes superlaterally and attaches to the fabula or the posterior lateral joint capsule or plantaris muscle. So, now, just let's go back and look at a normal anatomy scan. So, let's just look at the normal anatomy scan and understand the anatomy better. So, now, I hope my screen is visible to all of you. So, here what we see is this is an axial PD image, okay? I'll just take a sagittal fat-saturated image also. So, this is actually my medial femur, my medial tibia, my anterior and posterior horn of medial meniscus. And what you see over here, this is my posterior medial meniscocapsular junction area and the posterior medial corner area, right? Now, let's understand the anatomy so the coronal image will be more like a scout for you so you can understand at what level we are looking at. So, now, here, as we are going from cranial to caudal, okay, this is my medial femur and what you see, this structure over here, so you can see there is a nice black structure, a long black structure over here, okay? The anterior half of the long black structure is actually my medial collateral ligament. The posterior half of the long black structure is actually my posterior oblique ligament. So, this entire long black structure, you can just divide it into half. The anterior half is the medial collateral ligament, the posterior half is the posterior oblique ligament. Now, when you correlate on the coronal images, so what you see this entire structure, this is nothing but my superficial medial collateral ligament, okay? And as I go posteriorly, now what I see over here, this is not the MCL, it is actually the posterior oblique ligament. So, you can see this is my posterior oblique ligament, this is my posterior oblique ligament, this is my posterior oblique ligament, and now it will go and merge with the capsule in this region. So, as I go below, okay, you can see that how this posterior oblique ligament is nicely merging with my posterior capsule. So, this is my posterior medial joint capsule and it's nicely going and merging with the posterior medial joint capsule. Now, again, we go up, so here what we see is the, now let's look at the second component. So, this is my medial gastrocnemius and what you see over here, this is my semimembrinosis tendon. Now, again, as I'm going inferiorly, okay, before reaching up to the joint line. So, here if you'll see, we are still above the joint line, we're about almost a centimeter or so above the joint line. You can see that there is a small black structure that is separating out from the semimembrinosis tendon. Now, this is the capsular arm. So, this nice black structure which is going towards the capsule, this is the capsular arm of the semimembrinosis tendon and if you'll see, it will go and join the capsule in this region. Now, as you go inferiorly, okay, so this is my main tendon, this is my capsular arm. Now, as I go inferiorly, I've already told you that the anterior and the direct arm are not well differentiated on an MRI. But, let's try whatever we can make out. So, here, again, I'm going up, okay, at this level, so you can see this is my semimembrinosis muscle, myotendinous junction and this is the semimembrinosis tendon. Now, as I go over here, you can see there is a nice groove, okay. So, there is a tubercle over here and a nice groove over here and the tendon is going and attaching on the tubercle and the adjacent groove. Now, let's come down to this level. So, as we go from ancient, the two arms are there. So, this is all the rest of the arms and this is the capsular arm. As you go inferiorly, it actually forms a wider fan shape structure, okay, which goes in attaches like this. Now, of this fan shape structure, what you see, this is my this is my direct arm which goes and attaches into the tubercle. So, see, it's well nicely coinciding. So, this is my direct arm which is attaching to the tubercle and the adjacent groove. What you have is few fibers are going anteriorly. So, these are this is my anterior arm of the semimembrinosis tendon. So, my direct arm, okay, let me just label it so that you guys don't get confused. So, this is the direct arm. This is the anterior arm, okay. Now, as I go inferiorly, you can see there are few thin fibers which are extending inferiorly. These are actually difficult to appreciate but they go deep to the POL. So, this is my POL and the MCL and they go deep to it and they will attach just above the MCL region. So, there are thin fibers that go down and this is nothing but my inferior arm, right?  Let me label this also, okay. So, this entire thing as we go back up this is my semimembrinosis tendon, okay. As you go inferiorly, you can see that an arm is coming out of the main semimembrinosis tendon going towards the capsule. So, this is my capsule around.  What the tendon that attaches onto the tibia posterior medially in the posterior medial tubercle and adjacent groove. This is my direct arm. Few fibers will go anteriorly and attach to the anterior aspect of tibia. In fact, these few fibers, what I'm talking about that go anteriorly are better seen on a coronal image. So, here you can see this nice or void black structure over here. So, this is nothing but my anterior arm. So, these structures that are going anteriorly is actually the anterior arm. Anterior arm normally has some hyper intense signal inside it because of the magic angle artifact. So, this should not be mistaken for a tendinosis or a tear. Similarly, because of the fan shaped attachment, you can see that there is some intrinsic linear hyper intense signal over here. You can very well appreciate that is again because of the fan shaped attachment and should not be mistaken as a tear and few fibers extend inferiorly and this becomes the inferior arm. So, now we have discussed POL, we have discussed semi-membrinosis tendon. Now, let's look at the OPL or the oblique popliteal ligament. So, this is my capsular arm. This is my posterior medial capsule. This is the posterior medial menisqua capsular junction and what you can see this black line going all the way circular line. This is nothing but your posterior horn of medial menisqua. So, this is the posterior medial junction or the capsule. Now, this structure that you see that is coming out like this, this black structure is which is actually nothing but going along the capsule like the thickening of the capsule. This is your OPL. Now, OPL actually traverses all the way to the top. So, it actually goes superolaterally and attaches somewhere to the posterior posterior lateral femoral or the adjacent fabula. Now because it is traversing from medial to the lateral aspect it is not only an important component for a posterior medial corner but it is also an important component and provides stability to the posterior lateral corner as well. So, this is my oblique popliteal ligament. So, we have discussed all the major components. So, again, revising quickly, we have going from top to bottom. What you see first is your posterior oblique ligament behind the MCL. As you go inferiorly, you begin to see the semimembrinosis. We have discussed all the arms of semimembrinosis. As you go inferiorly the posterior oblique ligament will join with the posterior medial junction or the posterior medial capsule. From the capsular arm and the posterior medial capsule, what arises is your oblique popliteal ligament. So, once we have discussed with the anatomy now let us just go back to the prapavapoint presentation and look at what is the importance of these structures and why are we actually reading them in the first place. So, what are the functions of posterior medial capsule? The first thing is let us discuss about semimembrinosis because semimembrinosis is the main dynamic so it is the main dynamic stabilizer of the posterior medial capsule. The rest of the stabilizers that is your ligaments, they are actually the static stabilizers whereas semimembrinosis being a tendon it is a dynamic stabilizer of the posterior medial corner. It causes internal rotation of TBR during flexion. Another important job is that it pulls out the posterior horn of medial meniscus during flexion and prevents its injury by compression between the medial femoral and TBR contact. So, if you would have noticed the direct and the anterior arm they actually go behind the posterior medial capsule and insert on to the TBR. Plus, it also has a capsule expansion. So, semimembrinosis tendon has got some insertions on to the posterior medial capsule. The posterior medial meniscus capsule junction in turn is attached to the posterior horn of medial meniscus. So, whenever there is a contraction of the semimembrinosis which happens during flexion of the knee, it will put a traction on the posterior horn and pull the posterior horn further peripherally so that it does not get squashed between the medial femur and medial TBR during flexion. That's how it prevents the posterior horn medial meniscus injuries during flexion. Now, what are the functions of the posterior medial corner as a whole? Now, PMC is actually taught in extension and lacks in flexion. We can see the PMC structures, in fact the posterior oblique ligament and everything very well because we perform the knee MRIs in extension position and they are actually taught in extension. It is an important stabilizer for valgus stress in extension. So, the important thing is that in extension it is an important valgus stress stabilizer. By valgus stress means what is valgus? Your distant limb is actually going away from the midline which means that whenever there is a valgus stress, in fact, even if you try to just put a valgus stress on your knee, there is a stress that is felt along the medial compartment of the knee joint. So, it actually stabilizes against the valgus stress so that the medial compartment does not open up whenever there is a stress on the medial side of the knee. It is lax inflection so per se it does not have or it does not provide a lot of stability in case of a flexed knee. Hence, MCL becomes the primary stabilizer of valgus stress inflection. So, in an extended knee besides MCL even your PMC is an important stabilizer for the valgus stress whereas in the flexed knee it is predominantly only MCL which is a primary stabilizer for the valgus stress. What is the use of this knowledge? Whenever there is a medial compartment knee pain what the orthopath is going to do is a valgus stress test or an abduction stress test. Now, this valgus stress test is nothing but the orthopath is going to apply a valgus and an abduction force on the knee joint. This is done at 0 and 30 degree flexion. If there is opening up of the knee joint which indicates that there is valgus instability in at 0 degrees it is because of the MCL at 30 degrees it is because of the MCL injury. So, as we know the inflection MCL forms the primary stabilizer of the valgus stress. So, in 30 degrees it is the MCL which is injured if there is a valgus instability if there is no valgus instability at 0 degrees which means in extension it indicates that your PMC is intact. But if there is a valgus instability even in extension it indicates that added to MCL even the PMC is injured. So, that is how you can differentiate between the valgus stress and abduction stress between the MCL and PMC injuries on the valgus stress test. I will just repeat this again. So, in valgus stress test you apply the valgus stress on the knee joint inflection that is 30 degree flexion and in extension. If in extension there is no instability it means that your PMC is intact. But if in extension there is valgus instability meaning there is opening up of the medial knee joint space on valgus stress it indicates that added to MCL there is also PMC or the posterior medial corner injury. Other functions of PMC is that it is a secondary stabilizer for anterior translation.  It acts as a secondary stabilizer for anterior translation so it can provide anterior stability in ACL deficient means. So, this is important most of the times whenever the ACL sorry, most of the times whenever the ACL is torn you will get anterior instability. Some patients however we found that they have found is even in ACL deficient needs there is not much of an anterior instability which is because the PMC is actually now acting as an important stabilizer and preventing excess of anterior translation. It also provides it also prevents excessive posterior translation and similarly hence it can provide posterior stability in posterior in ACL deficient needs. So, three important things it is an important stabilizer for the valgus stress particularly in extension. It is a secondary stabilizer for anterior translation and is useful to provide anterior stability in ACL deficient needs. It is also a stabilizer for posterior translation and can provide posterior stability in ACL deficient needs. So, this is what are the functions of the PMC. Now, so what is the bottom line? Why are we learning all of this stuff? This is because PMC injuries if not repaired can cause ACL or ACL graft failures. So, just like what you heard about posterior lateral coroner, why is posterior lateral coroner important to be addressed? Because if the patient is undergoing an ACL or a PCL reconstruction surgeries and if the posterior lateral coroner is not addressed there is a risk of graft failure in the future. Similarly, if the patient is undergoing ACL and PCL graft repair and the PMC injury is not addressed, it can result into graft failures. Because as we have seen it is a secondary stabilizer both for the anterior and posterior translation. Okay, so PMC injuries, isolated injuries are rare. So, isolated injuries are rare. What we usually get is PMC is injured with other ligaments like ACL, PCL and your MCL. Whenever there is a PMC injury it can result into chronic valgus instability in extension. For obvious reasons it is an important valgus stress stabilizer in extension. It can also cause another instability pattern which is called as the anterior medial rotatory instability. Okay, it sounds complex but it is not. What happens is, there is instability of the TBR so there is external rotation and anterior subluxation of TBR relative to the femur. If you can understand it is actually anterior so it prevents valgus stress and it also prevents excessive anterior translation. Now if the PMC is injured obviously the knee will start going outwards so there is the TBR will start going outwards so it goes into external rotation and there is obviously anterior translation will also happen so there is anterior subluxation of TBR relative to the femur. Patients who have symptomatic AMRI, they usually have both MCL and PMC injuries. So and patients with symptomatic AMRI will almost always have the POL component as injured. Other components are also injured but it is found that POL is almost always injured whenever patient has a symptomatic anterior medial rotatory instability. So as I have told you again AMRI is caused by injuries of both of these. Now what happens is why again this is important usually isolated MCL injury meaning nothing else is injured it's only the medial collateral ligament which is injured. These patients are usually treated conservatively but whenever there is simultaneous PMC injury there is increased chances of developing a symptomatic AMRI and hence these patients actually require surgical management. So this is again important only MCL injury is usually treated conservatively but the treatment changes to a surgical management if there is an associated PMC corner injury because there is increased chances of development of anterior medial rotatory instability and because of the development of AMRI there is some instability in the medial compartment of the joint and it eventually results into an early medial compartment OA. So this is again a take home point that why we need to address PMC injuries one is we've already discussed that if not repaired it can result into graft failures another thing so this is when the patient is undergoing surgery but we need to add something else in the surgery whereas the second point is where actually the plan was conservative but now the plan has become surgical because along with MCL there is a PMC injury and it can cause symptomatic AMRI. So eventually the patient's management will completely change from conservative to surgical. The next thing is similarly you have if there are isolated PCL injuries usually we treat them conservatively because PCL is known to heal very well or remodel very well but if there is a simultaneous PMC injury along with a PCL injury again a surgical management is considered or can be considered in this patient depending upon the clinical examination because these patients usually develop symptomatic AMRI and eventually they will have medial compartment OA. So third point, third important take home point is PCL plus PMC injuries again a surgical management can be considered. So these are the three major reasons that we need to address PMC injuries. Now let's just look at the cases so we are just going to look at a couple of examples of posterior medial corner injury ranging from low grade to high grade injuries so that all if we just get an idea that how exactly these injuries look like. Now most of the information regarding a posterior medial corner you will get on a surgical and actual image. First obviously we look at a fat saturated image so I am going from medial to lateral so basically the reason we look at the fat saturated image is to understand where all which all areas are showing injury. So the most medial most structure this is a very important thing which all of you should actually put a habit of looking at it. This gives a very good idea if there is any MCL and a PMC injury so if I will just put a coronal image over here so here you can see that this image is actually correlating along my MCL and posterior will be my PMC. So when you see a lot of soft tissue edema always go and look at the medial collateral ligament and the posterior oblique ligament in such patients. So here you can see that there is obviously some injury to the MCL and the POA. Now as we go further medially what we see is there is some edema so this is my posterior horn. This is my posterior medial joint capsule and the junction so there is some soft tissue edema in the posterior medial joint capsule and junction and as you go further medially or towards the midline what you see is that there is an ACL there in this patient. The PCL looks intact and then when we go laterally what you have is your posterior lateral compartment or sorry the lateral femurative compartment which we won't be discussing. So here you have so this patient on the first look has an ACL injury there is some soft tissue edema along the posterior medial corner and there is surely some injury of the medial collateral ligament and the posterior oblique ligament which is also a component of the posterior medial corner. So now let's just look at the axial images because most of these structures are well recognized on axial images.   Now we have seen we have seen the normal images and it's actually pretty thin so this is how thin this is how thin it should be the posterior oblique ligament should be as thin as this. But here what you see is that it is thickened there is hyper intense signal within and also when I come over here I can see that there is a lot of soft tissue edema. So I know that at least there is some load to intermediate grade posterior oblique ligament injury obviously there is injury to the fibres of the medial collateral ligament with soft tissue edema. As you go inferiorly again you can see that there is some edema in the posterior medial junction or the posterior medial capsule. So here I can see that there is edema in the posterior medial capsule. So there is at least low grade injury of the posterior medial meniscus capsule junction the posterior horn of the medial meniscus looks pretty okay. And now let's look at the, I'll just get this out. So now let's look at the semi-membrinosus tendon so the semi-membrinosus tendon in fact looks pretty okay. So there is not much of an injury. This is, as I've told you, do not label this as a tear. This is nothing but the magic angle effect of the anterior arm of semi-membrinosus tendon. So the semi-membrinosus tendon looks okay. And finally what you see is your posterior, sorry, your obliquial ligament which also looks pretty much okay.  So there is not much of edema that is there okay. So in this region, this is my posterior oblique ligament and that there is not much of soft tissue edema here. So this is a pretty normal sorry, this is a pretty normal oblique peculiar ligament or the OPL. So coming down what all stuff this patient is having one is obviously the most important is that the patient has an proximal third ACL tear besides that the patient has low to intermediate grade injury of the posterior oblique ligament or the POL. There is some low grade injury of the posterior medial meniscocapsular junction with some soft tissue edema. So added to ACL injury this patient also has low to intermediate grade, sorry besides that this patient also has low grade medial collateral ligament injury at the femoral attachment. So you've got a full ACL tear, you've got a low grade femoral attachment MCL injury and you've got low to intermediate grade posterior medial corner injury particularly involving your POL and your posterior medial junction capsule. Okay, so this is the first scan, I hope all of you are clear with this. Let's go at the look at the second scan now. Okay, again we look at first only the fat saturated image to understand the structures that are injured. Now this, I'll just open a coronal so that you understand which will act like a scout for all of you. So just look at this image, okay, use this only for a scout. So here I'm coming from all the way from the periphery and look at the amount of soft tissue edema that is there. Okay, so we are this is the bone. So this is where my MCL and my POL is supposed to be located and you can see that there is a lot of soft tissue edema here. So I know that there is at least intermediate to high-grade injury of the MCL and POL. I can make that judgment just on this one image. Now as I go further immediately, sorry, further towards the midline, what I can see is that my posterior medial cap, meniscus capsular junction is also showing a lot of soft tissue edema. Okay, this is where my semi-membrinosis is inserting. There is some soft tissue edema in the semi-membrinosis direct arm insertion as well. So you can see this is my nice tubercle. This is a small groove. So this is the at least there is some low-grade injury of the semi-membrinosis and as I go here, you can see that even posterior to PCL where there is a some amount of soft tissue edema. So there is at least a low-grade OPL injury. Now besides that, the most important thing is that the patient has a PCL evulsion fracture with an intermediate-grade ligament injury itself and obviously there is a full thickness ACL tear. You can see the ligament fibres are flipped over here. So this I'll show you well on the PD image. So here you can see that there is a nice PCL evulsion fracture with an intermediate-grade PCL injury. There is really no fibres that is attaching. There are no anti-accruciate ligament fibres that are attaching at the femoral attachment. So it's a full-thickness ACL tear and you can see that the ligament fibres are actually flipped in the anterior intercondylar notch. Now let's look at the coronal images. So again, we are going from anterior to posterior. This is my MCL. You can see there is an injury here. In fact, there is a full-thickness tear of my superficial fibres of the MCL. So there is a full-thickness MCL tear. Now let's put the actual image so you can understand at what level we are looking at. So this is the site of injury. Now this is the entire MCL and POL. You can divide it into half. So this is my MCL. This is my POL. Now what I am looking at is the POL. And you can see that there is a high-grade tear of the POL as well. This is a high-grade tear of the POL. So this patient is actually not only having a near-full-thickness or in fact a full-thickness tear of the superficial MCL, but there is also a high-grade tear of the posterior oblique ligament. As you go down on the axial images, you can see that the posterior oblique ligament is injured here. Also the capsule is not looking good. So this is the menisco capsular junction. It is thickened. We have already seen that there is a lot of soft tissue edema in the menisco capsular junction. So there is an intermediate-grade posterior-medial menisco capsular junction. Injury on the axial images you can get magic-angle artifact here, but this is surely not a magic-angle artifact. We have already seen that this coincides to the injury. So there is a low-grade injury to the direct arm of the semi-membranosis tendon and along with that this is my capsular arm and this is my OPL. So here you can see that there is a low-grade injury of the OPL as well with a lot of soft tissue edema in that region. So here there is a lot of soft tissue edema. It's not a tear. It's just a low-grade injury of the OPL. So now summarizing, we have a full-thickness ACL tear at the femoral attachment. We have a PCL-evalgent fracture at the tibial attachment. We have a full-thickness proximal third-fibre stare of the superficial MCL. We have a high-grade tear of the POL. We have intermediate-grade injury of the posterior-medial menoscope capsule adjunction. We have low-grade injury of the direct arm of semi-membranosis and we have no-grade injury of the OPL. So it's practically involving all the components of your posterior-medial corner. So while putting in the impression, you not only have to mention about your ACL, PCL, and MCL injury but you also need to tell them that there is at least intermediate to high-grade posterior-medial corner injury. This patient will undergo an ACL graft repair may or may not undergo a PCL-evalgent fracture fixation but this patient will surely need an ACL graft repair and if the posterior-medial corner is not addressed, this patient can land up into a graft failure in the future. So this is how you need to correlate everything and put it together in your report. Now let's go for the third quiz quickly. Since now you've understood everything, I'll be just running a bit fast. So looking at the sagittal images again, the medial aspect, this is my MCL, this is my POL. You can see very nicely, this is my MCL, this is my POL. MCL is showing at least a low-grade injury. POL looks like an intermediate-grade injury at least on this one image. As I go further towards the midline there is a posterior-medial meniscocapsular junction injury. In fact, this patient also has a ramp lesion. So you can see that there is a discrete fluid signal in the posterior-medial meniscocapsular junction. So this is nothing but your nice ramp lesion. Okay. Your semi-membranosis over here looks okay. So not much of a semi-membranosis injury and as you go further towards the midline, the OPL also looks pretty much okay. So there is not much of soft tissue edema, so obviously not a intermediate or a high-grade OPL injury. Let's look at the axial images. So here, as I told you, the MCL is just going to be like a low-grade injury. If you look at the coronal images also, so what this nice black structure that you see going all the way through and through, this is your MCL. Okay. Now, if I go slightly posteriorly, you see a lot of injury over here. This is not your MCL. This is your posterior oblique ligament. So in fact, MCL is a low-grade injury but your posterior oblique ligament is intermediate to high-grade injury. So you can see the entire thickness of the fibres is involved. It is not a tear, but it is surely injured. It is almost three times the normal thickness. So MCL is a low-grade. POL is intermediate to high-grade injury. You also have posterior medial menoscope capsular junction injury along with ramp lesion. I am looking at the semi-membranosis. Already on sagittal, we have seen that it is normal. Even on axial images, we have seen that it is pretty normal. This is magic angle effect of the anterior arm. You can see the direct arm is pretty good and normal. And also your OPL looks okay. So it is mainly your that obviously this patient had an ACL tear. So to summarize, ACL tear, along with that you have a low-grade MCL injury but an intermediate to high-grade POL injury. Intermediate grade posterior medial menoscope capsular junction injury with posterior medial menoscope capsular junction tear which is your ramp lesion and your rest of the components of the PMC corner are good. So next, let's look at the next case. Again, we are looking at the sagittal FS images going from going from periphery inverse. Again, from the peripheral image I can identify that MCL is at least an intermediate grade injury and my POL is at least intermediate to high-grade injury. Now let's go towards the midline. So here obviously there is posterior medial corner injury okay. Besides when you go towards the midline, you can see that probably there is some low-grade injury of the semimembrinosis but not the tear or a high-grade injury, some low-grade injury of the semimembrinosis. There is obviously some intermediate grade injury of the OPL and besides that what this patient has is an avulsion fracture of the PCL. So this is a nice avulsion fracture of the PCL with a very low-grade injury to the ligament itself. ACL per se is not torn, may be a low-grade injury but surely not a tear. We'll confirm that on a surgical PD image. So actually the in fact the ACL looks pretty good. So ACL is not torn, low-grade PCL injury and a PCL avulsion fracture. Now with this let's look at your posterior medial corner on the axial images. So we've already pretty much diagnosed everything about the posterior medial corner. What we're going to do is just confirm our findings. I'll just open a coronal image along with this. So here now what we see is this is my MCL injury. So if you see now in this case I'll just first show you the coronal images. This is what is your superficial and deep fibers of MCL. So here this is my superficial fiber of MCL. There is intermediate grade injury at the femoral attachment of superficial fibers of MCL and what you see over here this is your deep fiber of MCL. So this is my medial meniscus ok? What is this? is your menisco terrorists .. this is my menisco femoral component going from the medial femur this is my menisco femoral component going all the way from the femur to the meniscous and this is my menisco tibial component going from the menisco to the tvia. So if you see that menisco tibial component is like in intermediate grade is in fact the full thickness tear. So this patient has about intermediate grade superficial MCL injury but a full thickness tear of the deeper fibers of the menisco femoral component. So this is the MCL now as we go. So this is my intermediate grade MCL intermediate to high grade because deeper fibers is actually a high grade injury and as you go posteriorly what you see this entire thing is your POL. So you can see the POL is actually a high grade injury. It is really thickened okay so nicely thickened POL and here also you can see a lot of soft tissue edema in it. So high grade POL injury and the rest what we've already discussed is your meniscocapsular junction injury with a ramp lesion. So here this is my so this is my meniscocapsular junction injury as I go further inferiorly okay. This is my capsular arm so this is my actually OPL. So you can see that there is a low grade injury to the OPL as well okay. This is also my OPL and there is some soft tissue edema in this region. So you can appreciate the soft tissue edema adjacent to the OPL. So it's like a low to intermediate grade OPL injury and as you go inferiorly you can see that there is some edema in the direct arm of the semimembranosis here you can appreciate it. So there is a low grade semimembranosis insertion injury as well. So this patient to summarize has a PCL avulsion fracture with a low grade PCL injury. This patient has intermediate to high grade MCL injury particularly involving the deeper fibers of the MCL intermediate to high grade POL injury along with that this patient also has a posterior medial meniscocapsular junction injury okay. Here you can see this and along with that a low grade semimembranosis injury and an OPL injury. So putting all of this together it is somewhere like an intermediate grade posterior medial corner injury because everything else is low grade except for POL which is a high grade injury. So it's putting all together it becomes an intermediate grade PMC corner injury. So again this patient will require as we've already told you this is a large PCL fracture so they may actually go and fix the PCL fracture because it's a huge fragment if they want to it is not slide it is not too much displaced. So again the management is between conservative versus surgical but if there is a lot of intermediate instability because intermediate root injury instability because this patient has an MCL tear which may require a repair and this patient has a PMC injury along with a PCL injury this patient may go for a surgery instead of a conservative management though your PCL evolution fracture is not displaced too much. Okay let's look at the last case now again from the peripheral aspect here you can see that my MCL is looking good so maybe it's a low grade injury because there is some soft tissue edema but POL is surely injured like a low to intermediate grade injury there is a lot of meniscal contusion so even the posterior horn of my medial meniscus is involved okay there is posterior medial junction injury which is like a low grade and what you see is that the semi-membranosis tendon is almost like an intermediate grade contusion. So again it's not a tear but it's more thickened so you can see that this is like an intermediate grade semi-membranosis tendon contusion and as you go over here may be a low grade OPL injury but not too much of an OPL injury. So further on what you can see is that your PCL is intact maybe a low grade at the TBL attachment but importantly there is an fragmented evolution fracture at the anterior cruciate ligament insertion. So here let's look on the axial images again so as I told you even on this image that MCL looks to be a low grade injury so you can see the fibers of the MCL are looking good is that there is a soft tissue edema around it so this is like a grade one injury or the sprain this is more of like a grade two injury where there is signal within the POL as well as there is thickening of the POL okay semi-membranosis as you go down you can see that there is edema within the direct head of the semi-membranosis and this is nothing but your intermediate grade semi-membranosis tendon contusion and over here you can see the OPL is not much injured so the OPL looks pretty okay right so this patient also has a intermediate grade posterior medial corner injury because there is an intermediate to high grade sorry there is an intermediate grade POL injury as well as a semi-membranosis tendon contusion so both static and dynamic stabilizers are actually injured in this patient. So this is how we need to put everything about the posterior medial corner in the reports you may not concentrate a lot on the low grade injuries of OPL and all but you need to really mention what is the status of the PMS of the POL and the semi-membranosis tendon and the posterior medial joint capsule this is really important to be put forth in the report and obviously as a whole the posterior medial corner what is the status of it we need to mention in the report. So now let's go back to the slides again for a last couple of slides so now there are mimics of posterior medial corner injury every edema in the posterior medial corner is not a posterior medial corner injury so please get a decent injury a decent history look for other ligament injuries because isolated PMC injuries are rare what can be the mimics of PMC corner injuries ruptured baker's cysts paramanical cysts pesansidine bursitis so here what you see is that there is a lot of soft tissue edema over here okay there is so you can see the whole posterior medial corner there is a lot of soft tissue edema in and around it but what you closely observe is there is some fluid over here okay and then you go on the next image you can see there is a small baker's cyst and it's actually nothing but a partially ruptured baker's cyst because of which there is a very baker's fluid leakage which is causing this reactionary soft tissue edema in the posterior medial menisco capsular junction so this is nothing but your partially ruptured baker's cyst next what we have is the another case where you can see that there is fluid and edema something like a cyst in the posterior medial menisco capsular junction again this is not a PMC injury if you closely observe this patient has a horizontal tear of the posterior horn of medial meniscus and this is nothing but the paramanical cyst third patient where there is a lot of soft tissue edema in the posterior medial menisco capsular junction but along with that there is a lot of fluid so if you'll see this is nothing but a pest tendons and there is a lot of fluid that is actually tracking along the pest tendons so this was nothing but pest answering bursitis when you go more towards the midline these are my pest tendons and what you see now there is not much of edema in the menisco capsular junction this fluid is nothing but the normal fluid in the posterior medial joint recess but otherwise there is no soft tissue edema in the posterior medial menisco capsular junction so this was nothing but a case of pest answering bursitis so the take home points is posterior medial corner is an important corner and its injury can change the management of the patient so we need to report them in our reports why it is important one thing is PMC injuries if not repaired can cause ACL or TCL graft failures if along with MCL isolated MCL injury there is also PMC injury it can cause symptomatic anterior medial rotatory instability and may require surgical management so again the management is going to change from conservative to surgical and along with PCL injury if there are PMC injuries the management may change from conservative to surgical PMC injuries again it is very important for us to report because we can see them on the MRI so we can really help the orthopods in their surgical or conservative management basically in their decision making we play a very important role so always look out for the posterior medial corner and make sure that you correlate well with other ligament injuries do not report any soft tissue edema in the posterior medial corner as a PMC injury isolated injuries are rare but if you see a multi-ligament injuries or if you see ACL injury or MCL injury please make sure that you've looked at the posterior medial corner along with your posterior natural corner and reported them in their report thank you thank you Dr. Chatali for this informative discussion and the way you explain made everything very clear and look easy for this very important corner of the knee there are few questions one is are ramp lesions limited to medial meniscus or can occur laterally as well no ramp is by definition it is a posterior medial meniscus capsular junction in fact we have discussed ramp lesion in the radiology journal club in previous year as well which was discussed by another speaker ramp is one to one and a half centimeter of the posterior medial meniscus capsular junction whenever there is a tear in that junction we call it as a ramp lesion on the posterior lateral aspect you do not have a proper meniscus capsular junction what you have is the popularity of meniscal fascicles and the ligament of wrist work so these provide stability to the posterior horn of lateral meniscus and what we develop in them is the wristburg rib tear on the lateral meniscus where the tear is present in the posterior horn along the ligament of wrist work and this is also seen in ACL injuries so ramp is posterior medial wristburg rib is posterior or posterior lateral meniscal tear okay and the next question is in what image in finding a knee MRI should we start suspecting the PMC injury apart from the graft failure of pre-op cases so all the ligament injuries that's what I've told you in the last slide all the ligament injuries are ACL your PCL your MCL injuries or multi-ligament injuries you need to look out for your posterior medial and posterior lateral columns right and this last question like low grade intermediate grade and high grade is it like low grade is spring intermediate is a partial tear and high grade is a complete tear is this a universal terminology basically kind of yes but we don't use it in the report okay what we use it as basically what you're saying is right low grade is g1 high grade intermediate is g2 and high grade is g3 but if you see a moderately thickened or I mean I've shown you a couple of images where the POL was very much thickened okay but you can't discreetly appreciate a tear but still that goes into a high grade injury okay so it is more on an eyeballing if you just see mild thickening of the ligament with perilligamentous edema that's a low grade injury if you see some thickening some intra substance hyper intense signal within the ligament and perilligamentous edema that's an intermediate grade injury partial thickness tear you always put it as an intermediate grade tear and you can give a percentage thickness that is involved which will give the orthopod a better idea like if it's less than 50% thickness or if it's more than 50% thickness so broadly speaking g1 g2 g3 is low grade intermediate grade high grade but high grade does not always mean a high that it has to be a complete tear there can even be a high grade injury where the ligament is really thickened a lot of hyper intense signal the fibers are mushy and you cannot identify them thank you Rokchadali once again for taking these doubts as well in detail so I think with this we can conclude today's journal club and it was really informative it will be shared on our youtube channel by Indian radiologist so you can revise these later on and make your reports even more importantly crisp for the referring physicians