Come along to another exciting session where we will be teaching you the essentials of upper limb anatomy and common orthopaedic conditions. We welcome pre-clinical students too to get your anatomy revision in before exams!
SUPTA upper limb anatomy session 1
Summary
This on-demand teaching session will cover upper limb anatomy and how to relate structure to function, from the shoulder to the hand. We'll explore the different elements of the shoulder that allow for a wide range of motion, including its joint structures, ligaments, and muscles, that create a complex but highly evolved system that supports complex movement. Additionally, we'll look at the balance between mobility and stability, and the knowledge checks at the session will help medical professionals to better understand shoulder mechanics.
Description
Learning objectives
Learning Objectives:
- Discuss the anatomy of the upper limb and the structures involved.
- Identify the major ligaments and muscles involved in shoulder stability and mobility and explain their functions.
- Demonstrate knowledge of the relationships between structure and function and the role of fail-safe mechanisms in the brachial plexus.
- Describe the range of movements available at the shoulder joint and the complex network of joints involved.
- Answer quiz questions about the components that contribute to shoulder stability.
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Computer generated transcript
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The following transcript was generated automatically from the content and has not been checked or corrected manually.
Yeah, just let me know when you've got your slides up. Okay. It's just uploading now. So, yeah, I think you should be able to present when slide tree on what has been. Yep. Perfect. All good. Uh I've never used this platform before. Oh, yeah, don't worry, I'm fairly new to this. Uh Hi, everyone. I thank you for coming today. I'm Rishi, 1/4 year indicating medical student at the Uni of Leicester and I'm one of the education reps on Sumpter today. We've got Paula with us. Uh also 1/4 year uh indicating medical student uh from Kings. She's currently integrating uh in anatomy. Is that right? Uh Anatomy uh also at King's and her interest line uh emergency medicine and she also enjoys teaching in free time. So Paula soldiers. Thank you. Um Hello, everyone. I am really happy to be here today. Um And I'm gonna be taking you through some upper limb anatomy. So um hopefully you can all see my slides and I'll be taking you through the full upper limb. So, from the shoulder, through the arm and the elbow down to the forearm and finishing with the wrist in hand um as we can expect today. So my uh the easiest way that I found to learn anatomy is to relate structure to function. Um And if we think about the main function of the upper limb, it's responsible for both fine and gross movements. So gross movement in order to broadly move our hands and our limbs around in space and then find movements to slightly adjust our muscles and perform movements such as opposition or fine grip. And so the best way I think to learn kind of a complicated system as the upper limb is to relate um the structures that we find in it to the functions that they're supposed to be performing. So um if complex movement is needed at the upper limb, then we need a vast network of nerves in order to supply the muscles involved. So here we are our friend, the brachial plexus. Um We start with our nerve roots from C five down to T one. Um They merge into cords and then superior, middle and inferior um trunks and then our lateral, our lateral cords, lateral, medial, restricted posterior cords, and then the five key branches of our brachial plexus. So that's are more muscular, cutaneous are auxiliary, our median, our radio are radial and our owner nerves. Um and that level of complexity not only allows for uh fine movement at the upper limb, but it also means that there's a fail safe mechanism in case of damage. To any one of these cords or these routes or trunk. So, fibers from other nerves can cover and compensate for damage portions of the brachial plexus, which means like our complex movement is very kind of evolutionary conserved. So, um we've talked a little bit about our nervous network, we'll talk about the shoulder first. Um So we're going to be talking about our muscles are extrinsic and intrinsic muscles. We'll talk about structures that actually form the shoulder joint and then we'll touch on the stability and mobility of the shoulder and the balance between the two. So firstly, thinking about movements at the shoulder joint, there's a very wide range of them. So we can perform abduction adduction, flexion, extension, rotation, elevation and depression at the scapula. And um this is just me kind of illustrating the diverse range of movements that are available to us at our shoulder joints and their how therefore we can classify the shoulder joint as a ball and socket because of the wide range of movement that is possible here. So, in order to possess this um this degree of freedom of movement, the shoulders actually made up of a complex between several different bones. So the scapula humerus and the clavicle and to some degree, the Stearman um as well, they articulate together to form the glenoid cavity here at the scapula um at the glenohumeral joint. Um and that will house the head of the humerus and then form are functional ball and socket. Um but there's a very kind of like, there's a, there's a complex system of joints here. So we have our sternoclavicular joint are acromioclavicular joint and our scapula thoracic joint, which is the joint that connects are scapula to our thorax. And that's kind of like a functional joint more than it doesn't have a capital or anything. It's just how the, the scapula sits on our thorax. Um The sternoclavicular joint is the only um kind of like so firm attachment of the shoulder to the actual thoracic cage. Um in theory, therefore, this might be a very unstable joint, but we can touch on this a little bit more later. Um The acromioclavicular joint, the glenohumeral and the scapula thoracic all work together in order to allow the head of the humerus to reach its full range of mobility. And so the joints have to work together to provide support for these movements. Um So we have quite a small articular surface relative to the size of the humeral head. Um The head of the humerus actually three times the size of the glenoid articular surface. Um And that means that at any point in any movement, only a third of the humeral head is actually in contact with the glenoid force at one time. And that basically means again that we have a very wide range of movement. So the shape of the bones um allows them to move in in in a better way. And the relative laxity of our joint capsule, that's the kind of a connective tissue that surrounds the joint then means that there's greater flexibility around this joint as well. So, we've established extensively that the shoulder can move, but what stops it from slipping out of alignment? So what's what stabilizes this joint that seems very kind of like very mobile but not very stable. And so the first thing is that the capsule, as we've discussed though, it's kind of like a lax um fibrous sheath, it will attach all the way around the joint. So it's very firmly attached to the humerus and to the scapula. And there's no gaps in it, which means that that creates kind of a negative pressure within the synovial membrane and sucks the actual humeral head into the li annoyed fossa, meaning that it's harder for the humerus to move out of alignment. Um We also have ligaments that sit around the joint. Um As kind of expected, we have our coracoclavicular and our coracoacromial ligaments which will stop the move the humerus from moving upwards out of alignment. And then we have our glenohumeral ligaments. So they're medial lateral, anterior, they kind of surround the entire joint capsule, they're very intimately related with the joint capsule and it will support movement in all directions. Um And then finally, our coracohumeral ligament will which will stop the kind of like anterior gliding of the humeral head because if you can imagine if the humerus tries to move backwards, it's got a whole thoracic Asian, a whole scapula at the back, stopping it from doing so, but nothing really at the front that will stop it from moving anterior except for this coracohumeral and then our glenohumeral ligaments as well. Um Also the angle of the actual glenoid faucet is then created by the position of the scapula on the thorax. So in shoulder extension shown on in the conflict middle, um the glyBURIDE fossa faces, yes, it faces uh anteriorly that supports that movement. Whereas in flexion, it will face upwards which will uh stop the humiral head from sliding off of the glenoid fossa. Um And so that means that sub stability and the support at this joint is very dynamic and it changes based on the movements that were performing. So, um we've talked a little bit about ligaments, we've talked about bones uh now onto some soft tissues. So we all we know and love the rotator cuff. We can remember it with the acronym sits. So S I T s and that's super spin Atis in for a spin Atis Terra's minor and subscapularis and those muscles will surround um the humerus and also around the uh the joint in order to support it as it moves. We've also got the green order labrum, which is this kind of like articular piece of cartilage which deepens the actual socket for the ball and socket joint and it adds a lot of support further to this. We have the long head of the biceps tendon which will merge with the superior portion of the green eyed labrum, which will add further support to the humeral head within that um within that socket. And so we have a lot of soft tissues supporting the joint as well. So it's not just that we have kind of like an array of bones, um kind of like in a more relaxed function. We have quite a dynamic system here, which will mean that our shoulders have actually very well supported. So we talked about our intrinsic muscles. Let's talk now about the muscles that will actually act at the shoulder. So other than our deltoids, we also have our, um we have a very large range of muscles that will um provide different actions at the shoulder and their attachments can tell us about their actions. So for example, um the trapezius will cover and it will kind of cover across the scapula. So we can kind of in for that, it will stabilize and move the scapula if need be, but it also attaches onto our upper humerus. Um So it is an important abductor of the arm are Latissimus dorsi i with its attachments to the shaft of the humerus will add up to the arm when it's contracting and then and so on and so forth are elevator, scapula, rhomboid minor and major will all move the scapula as they're attached to it, as you can see here on the right hand side. So, abduction is a tricky movement um because there's considerable interplay between several different muscles. So as you can see here, super Spinatus um is actually in charge of the 1st 15 degrees of shoulder abduction at which point are deltoid takes over up to 90 degrees. And then we've got our Serratus anterior and trapezius coming in up to 100 and 20. And actually, that is the range of humoral movement further after that, all of the rest of the abduction. So 122 180 degrees is conducted by the movement of the scapula and the scapula rotation on the thoracic cage. So it kind of highlights the importance of the joint complex itself and it's not just any one um muscle or anyone joint itself. It's the kind of like the importance of this complex. So, um I'm not quite sure how to do this. Is there an interactive way to do this? Um in terms of having knowledge checks, I've got some quiz questions here. So if you take a second, I don't know if you're allowed to type in the chat. Well, okay. Well, I'll give you some minutes to answer them for yourselves then. So which of these factors does not contribute to shoulder stability? Is it the labrum long head of the biceps, the super spin artist or the terrors major. So it's actually terrorism major. It does not contribute to shoulder stability. Um Yeah, absolutely. So, terrace major. Um And that's because we've spoken about the labor and deepening the socket. We've spoken about the long head of the biceps attaching onto the superior portion of the labrum and further supporting the humeral head. And we've talked about super spin not as being part of the rotator cuff. Um But terrace minor is actually part of the rotator cuff, not major. So, Terrace major is just uh living it's life, but it's not necessarily contributing to shoulder stability. So, um now we're going to talk a little bit about the arm, elbow and forearm. So we'll be touching on the anterior and posterior arm and we'll be putting it into context with movement at the elbow joint. So, um now that I've discovered that I can actually get responses in the chats. Can I ask um any movements that you can think of at the elbow and at the forearm, elbow flexion. Absolutely. Anything else? Flexion, extension, Pronation Super Nation. Absolutely. You've covered all of them. So we'll not be talking about Pronation super Nation just yet, but we'll definitely be covering extension and flexion. So, um we've got our primary flexor being biceps breaky and our primary extensive being triceps, breaky. Um But given that at the elbow joint itself, so not at the radio owner, but just at the elbow, our main movement is just in one direction. So we can flex and we can extend in one plane. What type of joint is the elbow joint then? What classification of joint? Mhm. Is it a saddle joint? Is it ball and socket? Like we've seen that the shoulder is, yeah, it's a hinge joint. Absolutely. It can only move in one plane. So it's a hinge joint. Um, and in order for us to be able to function properly and to have a proper um yeah, absolutely a hinge strange. So in order for us to have um the correct range of movement in our hinge joint, we need normal bone positioning. So our flexion happens at a carrying angle of around 12 to 15 degrees. And so that means that are normal elbow affection will move our hands into our midline and not just in the same kind of like plain as the humerus and that's very useful for eating and for protecting ourselves and important structures in our torso. But if we draw a line through the head of the radius along and another line along the shaft of the humerus, um they should intersect at the kind of like the middle of this humor, epic condyle and so on this X ray, this is used in trauma settings to make sure that our elbow joint is properly aligned and is not dislocated at any point. So, disruption to these lines or misalignment of them could, could indicate a fracture or a dislocation at this joint. And so what ligaments are normally integral to the structural stability of the elbow joint? Can anyone name a ligament that is important to the stability of the elbow joint? Okay. I'll just show you the diagram, it'll be fine. So um we have our main ligaments that's may and there's four of them, there's a lot more, but the main ones, there's four. So we have our annular ligament shown here in blue which forms a sling around the radius and it will support our pronation and are super nation. We have our ulnar collateral ligament which will support the owner side of our elbow. And then we have our radial collateral ligament which will support, which will support the lateral side of the elbow. And further to this as an extra one which sits underneath the annual ligament which connects the owner to the radius. And that's called the um quite quadrant ligament. And that will um support pronation and super nation, but also make sure that the owner and the radius don't separate from each other. Um And so these ligaments are same as the shoulder, they're broadly relaxed, they will be taught, bent certain movements. So for example, um the uh so for example, if you were to put a force on the lateral side of the elbow, that would stretch our ulnar collateral ligament, and it will prevent those bones from moving from each other, and that's how we stop these bones from becoming misaligned. So this is quite a busy slide. Ignore all of the labels on the diagram. I just wanted to include them here in case you wanted to have a look later. Um But our anterior arm muscles will broadly bi flex is of the arm. So if we think about their attachments, they'll be attached across the front of the elbow joint. And therefore when they contract, they'll contract our arm upwards. So there's three key ones to remember and all of them are innovated by the muscular cutaneous nerves. So the two main flexes are a bicep tricky and our bronchialis. But there's also an extra muscle here called the coracobrachialis, which is the only one here, which does not flex the elbow, but it rather helps the shoulder in movements like flexion and abduction. So it'll um and you can see based on its attachment where it will attach to our coracoid process from the coracoid process onto the shaft of the humerus. So it won't actually cross the elbow joint and therefore, it cannot act at the elbow joint. Um So those are our anterior arm muscles. What muscle have we already seen in the slides, which is the key muscle to remember for the posterior forum for the posterior arm even. So, if we, we've spoken about biceps Reiki, what are we going to talk about next in the posterior arm? Triceps? Absolutely. So we'll talk about triceps. Now, um triceps is responsible for elbow extension. As we've discussed, it's supplied by the radial nerve. Um that is the main posterior arm muscle that we need to discuss. And speaking of the radial nerve, all of the nerves that we've spoken about so far. So median radial owner, they all need to cross the elbow joint. And as you can imagine, if we have a large degree of movement and we flex and extend our elbow's quite frequently during just day to day life. They need to avoid the damage that comes from having like repeated movements over and over on the surface of these nerves. So they need safe passage across our cube. It'll fosse's. So the median nerve, it will begin medial to the humerus. So it'll begin kind of crossing over the medial surface of the humerus and it will cross over into our interosseous space. So that is the space in between the radius and the owner and it will terminate in a position lateral to the owner. Whereas the radial nerve, um we'll begin lateral to the humor to the humerus. It will cross over onto the lateral epic will cross over the lateral epicondyle into the posterior compartment of the forearm. So we've spoken about how um triceps is innovated. So uh the radial nerve is lateral to the humerus, supplying our triceps, and then it will cross over the lateral epicondyle of our humerus and into the posterior compartment of the forearm to innovate the posterior muscles there. And then we've got our own a nerve which has a bit of a funny course, it will begin posterior to the humerus, but it needs to end up anterior in order to supply our wrist and finger flexes. So it will begin posterior to the humerus. Ill cross behind our medial epicondyle into the anterior compartment of the forearm. And importantly, it'll travel through the cubital tunnel. So the cubital tunnel is um a point at which the ulnar nerve uh kind of like a little tunnel that the on the nerve goes through. And it's a point at which the on a nerve can become injured or compressed if there's trauma to this area. So these are the two main points of compression. So it'll travel underneath the arcade of Struthers and underneath osbournes band as it crosses into the shoulder, not into the shoulder, into the forearm. And um this is important because um if you have an ulnar nerve injury, it's important to check both of these points of compression because compression at one point can then very easily lead to inflammation and compression at the next one up for the next one down. So we've spoken about our nerves are median, radial and on the nerves. Can we think of any other structures that will travel within the cubital fossa, any other structures that will move that will exist in this kind of like area, the cubital fossa, radial artery. Yeah, the biceps tendon. Absolutely. What vein are we aiming for when we take bloods? So we have here uh radial artery, owner, artery or break your artery and our cubital artery as well here crossing. Um So these vascular structures also travel here. Um And it means that we have easy access for um taking blood's from people. But it also means that these vascular structures are potentially at risk if we have any issues like a fracture or dislocation at this point. Um So, yes, so that concludes our elbow and arm portion of the evening. Um But now another knowledge check. So which of these does not travel in our cubital fossa? See the cubital artery, it does travel in the cubital fossa. Do we have any other guesses? So be the on a nerve? Absolutely. So the on a nerve will travel posterior to the cubital fossa will enter the cubital tunnel and move in kind of like the posterior portion of the album. So now let's talk about the wrist in the hand. We're going to cover the bones of the wrist, the carpal tunnel, we're going to talk about anterior forearm muscles, we're going to talk about posterior forearm muscles. And then we're going to talk a little bit about cutaneous nerve distribution and jet. And of course, putting all of that into context with the movements of the fingers and the thumb. So, um here is the enormous range of movement that we can do our wrists and at our hands and our fingers, this is the center of kind of like fine movement in our upper limb. And it means that there's lots of little muscles involved and lots of little nerves involved. But the fact that we have such a wide range of movement means that we need a complex of joints and not just a single hinge joint like our elbow, but rather, um, a lot of different bones doing a lot of different things in relation to each other. So um we'll talk firstly before we complicate things about normal risk alignment. So the third metacarpal, so your middle finger is the central axis of your hand about which you can abduct and adducts your fingers. And that central axis of the hand needs to stay integral so that we're able to perform movements like opposition, which is when your pinky touches your thumb and opposition of each of your fingers. So your third metacarpal has to align with your capitate bone, with your lunate bone and then with your radius. And um all of those kind of like align together down the central axis of your hand so that you're able to perform movements about that axis. So here are carpal bones here at the bottom. They exist in the wrist are metacarpals which will be in the palm of our hands and then our phalanges which will be in our fingers and all of these bones are able to move in relation to each other in different ways. Um There's lots of different know Monix that you can use to remember the carpal bones. Um But essentially just start at one point, I'll start at the skate void and make my way around um like anti CAA quite. So we have our scaphoid bone which will articulate with our radius. We have our lunatic bone which will articulate with our radius and also our owner, a triquetrum which will mostly articulate with our owner. Um The pisiform bone which is a sesamoid bone which exists inside a tendon and therefore can kind of like there's a debate about whether or not it's a bone of the wrist at all or just kind of there is support. Um We have our hamate which um is important when we're talking about the carpal tunnel in a second, are capitate, are trapezoid and then trapezium. Um The way I remember this is that oid before. Um but it's a bit, it's a bit difficult to remember which way around they come. The important thing to remember here is that our scale avoid blood supply is retrograde and you know, directionally, which means that for example, in, I don't know if you can see it's quite small picture but it's fine. So in kind of like portion a of the scaphoid, it's got quite a good blood supply. B and C also have good blood supplies, but a portion of the scaphoid out after the waste of the skateboard, which is this kind of like narrowing point here at uh label D. The relies on the blood supply from A B and C in order to retain like be perfused. So if we, if you can imagine if we have a fracture in between C and D, that means that that portion of the scaphoid is now lost a blood supply. And um it can become a scheme it very quickly. So that is why the blood supply of the skateboard is very important and we've now covered our bones of the hand and the wrist. So um in terms of the risk stability, so the main um joint that we're concerned about here is the radial carpool joint. So it's articulation of the radius which has this angulations here with the scaphoid and lunate bones. And um as we've discussed, it has this angle here and that will limit our adduction of our hands. So we can abduct way more than we can add acct. And that's due to this angle of the radius, which I've exaggerated for um diagrammatic purposes here. Um So because of the large range of movement that we can perform our, our wrists and our hands, we need a quite a stable base of ligamentous support. Um And you can see here, the amazing kind of network of ligaments that connects all of your carpal bones together, in particular, um the bones around the capitate and around the scaphoid, um all kind of like radiate out from each other and we'll support movements at the wrist because we can perform quite a large degree of flexion and extension at our radio carpal joint. But finer movements will be happening in the kind of like intercarpal joint space, which is very complicated. And we don't really have a lot of time to get into it into a lot of detail. But we've also got ligaments that will support our metacarpals. Um And about our metacarpal joint, what movements can we do at our metacarpal joints? Well, so at our metacarpophalangeal joints, so these joints here, what movements can I do here? Flexion extension. Absolutely. So we can flex and extend our metacarpophalangeal joints. What else can we do here? So we can abduct and add Akhtar fingers as well. We can spread our fingers and we can put them together so that we're able to grip things differently. Yeah, absolutely. So because of that, this can be referred to as a saddle joint. Um because we can move into different planes and then at our fingers, my, my fingers are a bit funny. So anyway, um our fingers, what kind of movements can we do? Our distal and proximal interphalangeal joints? That kind of demonstrated here on the diagram. Yep. So you can flex and extend your finger. And that means that our distal and our prox proximal and our distal interphalangeal joints are both hinge joints because they can only move in one plane. So there's a lot of different joints going on in our hands. And that makes sense because we need a lot of different movements and a lot of different fine movements in our hands. And we've got quite a large network of ligaments that support those movements at the metacarpophalangeal joints. So the joint here that we've discussed as saddle joint, we have quite a lot of support for those movements. So I'll take you through the cross section. The middle bit in yellow is the proximal articular surface of our proximal phalanx. So it's like a cross section and we're looking into my finger. Actually, it would be more like this into my finger. Um We can see the dorsal surface which will have our extensive tendon and we can have, we can see our volar or are palmer's surface which will have our flex attendance. And there's two of them because we have a superficial uh yeah, a superficialis and a profundus tendon reflex attendant above our flexes deep to our flex is we have a palmer plate and that is the key structural support of the metacarpal phalangeal joints and of the finger in general, we will have a palmer plate at every single one of these joints. So we'll have one at the MCP JAY, one at the P I P and one at the D I P. In order to attach all of these um ligaments that support each of these joints, either side of that palmer plate, we have our interosseous muscles sheath and um the interosseous muscle is an intrinsic muscle of the hand that will do things like um like a single finger abduction and adduction or um adduction of your middle finger, either side. Um And these muscles are responsible for those kind of like more fine muscle movements of your hand. We then have our main collateral ligaments which are either side of the phalanx. Um And they will generally support the structure of the finger throughout and our accessory collateral ligaments will do the same. And then we have our extensive tendon responsible for extending our finger and any disruption to that extent attendant will then mean for example, if we have a disruption to um like for example, if you're catching a ball and you catch your finger and we break off our extensive tendon at the D I P, you can end up like me where you have a swan neck deformity of your finger um and a mallet finger as a result. So not swan neck, a mallet finger. That's okay. Yes. So that was our M CPJ. We'll talk a little bit about the anterior forearm muscles um which might feel a little bit less hectic to look at after that diagram. So we have our superior intermediate and are deep finger flexes and there's a very uh there's quite a few of them, but the main things to remember is that for every onerous, there will be a radial list. So if there's a flex, a copy onerous, there will also be a flex, a copy radia list and they will both be in charge um of flexing at our wrist. So Carpi means wrist, the superficial muscles of the anterior forearm are broadly wrist flexes except for pronator terrace. So Palmyra's longest will also be in charge of wrist flexion, pronator terrors will be as the name sounds a pronating muscle. And all of these muscles will be supplied by the medium nerve, except for flexor carpi, ulnaris, which will be supplied by the ulnar nerve, the intermediate muscles of the anterior forearm, our finger flexes. So it'll be our flexor digitorum superficialis in the kind of intermediate space of the anterior forearm. But it also plays a role in risk collection. But let's just simplify things. So are superficial compartment will be our wrist flexes are intermediate compartment will contain our finger flexes and are deep compartment will contain more finger flexes. So um all of our finger flexes will be um innovated by the medium nerve as well as our wrist, wrist flexes as well. So flexion broadly from the hand and the at the wrist will be um supplied by the medium nerve and the extent and the exceptions to that our flex a copy onerous and flex it and the medial portion of flexo digitorum profundus. So yes, this is very complicated and it will take you a few times of looking at this to make sense of it. But it helps to look at things to group things together broadly and then learn the small like little details. So if we just from this side, if we just remember the superficial compartment, will flex our wrist and the intermediate and deep compartments will flex, flex our fingers. That is all we need to know for right now. So at the posterior forum, there's a lot of muscles as well. So we have our superficial muscles um which have kind of like a very diverse range of functions. Um but they're broadly uh supplied by our radial nerve and then our deep muscles will extend our thumb and um they're also supplied by the radial nerve. So if we think the anterior compartment of the forearm supplied by our median nerve and the posterior supply of the forearm is our radial nerve. That is more than enough for the forearm. There is a lot of like little muscles. So for example, extensive induces appropriates that indicis appropriate refers to our index finger. So it will extend our index finger. The thing about a lot of these muscles in the anterior forearm is that their name will tell you what they're going to do. So, for example, um extensor carpi ulnaris will extend our wrist on the ulnar side and then extensive copy radiologist will extend our wrist on the radio side. And so on and so forth. So now let's talk about the carpal tunnel. It's made up of the roof being our flex a retinaculum, the floor become being trapezoid and our capitate bones are medial border is our hamate and our hook of hamate which will attach this flex, a retinaculum and the lateral border is our trapezium which will attach the other side of the flexor retinaculum. The things that travel within this, within this tunnel, our our flex a muscle. So flex a policies longest digitorum, superficialis and digitorum profundus. So all of our flex the muscles for our hand and um the median nerve as well. So where would you feel kind of parasthesia or pain or tingling or numbness if you have carpal tunnel syndrome? So, if we have carpal tunnel syndrome, we have compression of the median nerve. Where would we feel that in our hand? What is the cutaneous supply of the medium nerve? Does anyone know? Okay. So the continuous supply of the median nerve will be these kind of like your first finger, your second finger and then your thumb. So you'll have kind of shooting pains in this distribution here. If for example, there's compression in the cubital tunnel. So where the owner nerve travels, you'll feel um shooting pains or parasthesia or numbness in the ulnar nerve distribution, which is these kind of like the palmer surface and the dorsal surface of the little finger and then half of the ring finger. So our cutaneous hand innovation can tell us a lot about um different issues which might arise as a result of nerve injury throughout the um throughout the upper limb. Yeah. So now let's do a little knowledge check where nearly at the end and then I'm happy to take any questions that you might have. I appreciate. This has been a bit of a long session. Um Let's talk about this. So which of these does not flex the wrist, which of these muscles will not flex the wrist? So this is the second to last quiz question I have for you. Deep pronator terrace. Absolutely. So pronator terrace, as it says in the name will prone eight your hand and then our supinator muscle located in the posterior forearm will super Nate our hands. So if um if a muscle has an Axion, like for example, us are anterior forearm, we'll have our flexes and are pollinators and are posterior forearm, we'll have our expenses and are super nature's. So which of these is supplied by the on a nerve? And this is a bit of a tricky question. Be absolutely. So the medial portion of flexor digitorum profundus is supplied by the honor of the sensory supply of the thumb comes from both the radial nerve and also the median nerve. The the sensory supply to the posterior hand will largely come from the radial nerve except for the last two fingers, which will be the owner nerve and then extensive copy or no virus will be um will be supplied by the radial nerve. So it'll be, it's a little bit of like a confusing one in terms of the name. But if we just remember posterior compartment supplied by the radial nerve, anterior compartment supplied by the median nerve. So thank you so much for listening. Um And I'm happy to take any questions that you guys might have. Um Thank you so much for interacting as well. It's, it's always better when the audience has things to say. So I just feel free to drop any questions in the chat. Yeah. Okay. Cool.