in this video we're looking at the anatomy of the elbow joint whether you're a med student criming for tomorrow's test or you just found out that you tore your ulnar collateral ligament and don't really know what that is I got you covered we're going to go step by step through the bones of the elbow joint the ligaments that hold those bones sort of together are in place and finally look at two muscles that control movement of the elbow joint and at the end I'll have a blank diagram so you have a chance to practice all of this to make sure you really know all the parts of the elbow joint so let's uh jump to the Whiteboard and get started so here on the diagram I want to draw the elbow joint from two different perspectives we're going to have a lateral view as well as a medial view so the medial view is going to be looking at the elbow joint and the inside part right here that's closer to the Torso and the lateral view is going to be looking from the outside so we'll start with the bones the first bone that I have in the diagram is the humerus this is going to be the bone of the upper arm right here it's a single bone that goes from the scapula all the way down to the elbow joint where it's going to meet with the radius and the ulna up next we have the ulna now the ulna and the radius are really easy to confuse between each other so here's how I remember the difference between the two the radius is always going to be the bone that's going to go from the elbow joint to the side where your thumb is whereas the ulna is going to go from the elbow joint to the side where your pinky is and if you take your thumb you can move your thumb in this circular motion and when I think of a circle I think of well a circle has a radius and so because our thumb moves in a circular motion we have the radius that connects to the thumb on the opposite side we have the ulna which is always going to connect to the pinky side of the hand and I'm not sure why but ulna and Pinky just they feel like they go together right am I right tell me I'm right right so we have the lateral view of the ulna as well as the medial view of the ulna the other interesting thing about the ulna is it has this part that sticks out at the end here that's called the old cranin of the ulna when you feel the actual kind of point or end of the elbow here you're looking at the old cranin of the elbow and the old Crandon is the part that's going to kind of wrap around or articulate with these two tubercles of the humerus the radius we'll see in a second doesn't have an old cranin that's going to articulate there so the old crannon right here and right here is going to wrap around the humerus and it'll be the part that articulator actually sort of moves with the humerus whenever you bend your elbow joint there third bone we have in our diagram is the radius and the radius like I said is going to connect to the thumb side and it's going to articulate with the tubercle of the humerus we see that connection right here but like I said it doesn't have this part that actually wraps all the way around the humerus like the ulna does and then I'll also draw in the radius on the medial view in anatomical position which of course is somebody standing with their arms out to the side like this the radius is going to be more lateral and the ulna is going to be on the medial side and we can see that in the diagram here we have the radius which is on the lateral side it's in the foreground in this part of the diagram and we have the ulna in the foreground of the medial view so radius is lateral and ulna is medial at least when we're looking in anatomical position now the opal joint is an example of a synovial joint which means there's lots of movement and any synovial joint we're going to have articular cartilage that's going to be on the ends of all the bones that articulate or move across each other and the whole purpose of that is we want to reduce the amount of friction between the bones without the articular cartilage those bone bones would be rubbing against each other grinding each other down that's going to cause inflammation and a lot of problems with that joint we've got this smooth articular cartilage to reduce the friction between the bones and the elbow joint you can see that articular cartilage here at the proximal end of the radius proximal end of the ulna as well as the distal end of the humerus on those tubercles of the humerus now before we get into the specifics of the synovial elbow joint let's take a look at the radius and the ulna because they actually form a fibrous joint a fibrous joint is a type of joint that doesn't have a lot of movement you can't really move your radius away from your ulna there's a tiny bit of movement but not a lot so we need some ligaments to hold the radius and the ulna together as we're moving our arms around we've got this long sort of sheet of ligament called the interosseous membrane and it's going to connect between the radius and the ulna and we see that interosseous membrane right here that's going to provide some stability between the radius and the ulna and prevent much movement from happening now a little bit of movement does happen right we were able to kind of rotate our arm like this and so they kind of rotate around each other but that's much less movement than for example a synovial joint like the movement of the elbow one more ligament with a similar purpose is going to be the oblique cord oblique means not perpendicular nor parallel oblique is going to be kind of at an angle and so if you look at the oblique chord it goes at an angle between the ulna right here and the radius right there on the diagram we can see the oblique cord sort of peeking out from this lateral view but it's a little bit harder to see and again that's going to provide some stability and hold those bones together now back to the elbow joint which is the synovial joint meaning it has lots of movement we're going to have something called a joint capsule any synovial joint will have a joint capsule which is going to do a couple things first it's going to provide a lot of stability for the joint it's going to kind of prevent those bones from moving across from each other we don't want the humerus and the radius and ulna all separating out but it's also going to work as sort of a capsule holding in something called synovial fluid now we already talked about articular cartilage reducing the friction between the bones and the joint synovial fluid is going to be sort of a lubricant doing the same thing it's going to prevent much friction between the articular cartilage at the end of those bones but any sort of fluid needs to be held in somewhere so the joint capsule which wraps around the whole joint right here is going to hold that synovial fluid inside of it but the joint capsule doesn't provide enough stability so we need a series of other ligaments that are going to provide more stability and the joint capsule is able to provide the first of those is called the annular ligament which is I think is kind of the neatest or most unique one at least of all of these ligaments that we're looking at in the elbow joint that's because it starts and ends on the same bone it starts and ends on the ulna so we see that right here it connects to the ulna right there it's going to wrap around the radius and then connect to the ulna down on the other side right here and it acts as this sort of band that's gonna like I said start at the ulna wrap around the radius and connect back to the ulna and that's just going to sort of hug the radius and keep it in place up against the ulna so the annular ligament wraps around the radius and holds it tight against the ulna another ligament with a very similar purpose but a very different structure is called the quadrate ligament and this is going to be a ligament that goes directly from the radius to the ulna kind of in a straight line now I don't have it in the diagram because it's sort of covered by the annular ligament and it's just hard to draw in because it just literally goes straight from the radius to the ulna so here's a diagram that shows where that quadrate ligament is take a look it's going to go straight from the radius to the ulna holding those two together at the elbow joint so annular ligament wraps around the radius quadrate ligament goes directly from the ulna to the radius up next we have a ligament on both sides of the elbow joint we're going to have the medial collateral ligament as well as the lateral collateral ligament now both of these ligaments aren't really one ligament a piece they're a complex of ligaments that we call the medial collateral ligament and the lateral collateral ligament the word collateral there just means kind of like off to the side so we have some on this side and some on this side similar to the LCL and MCL that we have in the knee joint let's start with the lateral collateral ligament remember lateral means on the outside which is going to be the thumb side and so it's going to be the radius side the first part of this is called the ulnar lateral collateral ligament that was a lot I'll shorten it to ulnar LCL so that's going to connect this part of the humerus over to the ulna right here it kind of goes over that annular ligament and connects to the ulna which is really the ulnazon the medial side so this is a lateral collateral ligament that's going to kind of wrap under and connect to the ulna side you may also see this called the l u c l which just changes the order of what I just said instead of the ulnar lateral collateral ligament it's the lateral ulnar collateral ligament or the lucl for short the next part of the LCL is going to be the radial LCL the radial LCL is going to start kind of on the same spot of the humerus and it's going to go under or beneath or deep to the annular ligament and connect to the radius right in here and where's the owner LCL held the ulna in place relative to the humerus on the lateral side the radial LCL is going to hold the radius in place relative to the humerus on the lateral side or if that was a lot to remember just remember we've got a lateral collateral ligament on the lateral side that's going to hold the humerus and the radius and the ulna in place on the lateral side that radial LCL is oftentimes just shortened to RCL for radial collateral ligament I've already talked about the annular ligament but I want to make a point here that the annular ligament often is included in part of the lateral collateral ligament so you could say that the LCL is made of three parts the LCL has the ulnar LCL right here the radial LCL right here and it also includes the annular ligament the AL right there put all that together is the lateral collateral ligament next let's look at the medial collateral ligament so this is going to be another complex of ligaments on the medial or inside of the elbow a few directional terms will help with this the first one is going to be the posterior bundle of the medial collateral ligament posterior means kind of towards the back of the body whereas anterior means towards the front so the posterior bundle is going to be part of the medial collateral ligament that's more on the posterior or back side of the elbow whereas a lot of the ligaments we've looked at are sort of band shaped these long kind of narrow ligaments the posterior bundle however is more fan shaped so it's going to start kind of narrow right here and it's going to Fan out as it connects to the ulna right in here so we have the posterior bundle of the MCL next we have the transverse ligament of the MCL transverse means to sort of cut across something so you see right here that's going to be transverse because it's going to cut across let's say the posterior bundle for example or the elbow joint itself it cuts across the elbow joint so the posterior bundle which is fan shaped the transverse ligament and then finally we're going to have the anterior bundle or the bundle that's more in front that's going to be the third part of the MCL the anterior bundle is more of a band unlike the fan shape of the posterior bundle it's going to connect again the humerus to the ulna if you notice pretty much all of the medial collateral ligma is connecting the humerus to the ulna there's no part of the MCL that's going to connect to the radius remember the radius is on the lateral side the ulna is on the medial side as far as terminology a lot of times the anterior bundle is referred to as the mucl that would be the medial ulnar collateral ligament so if you see that term mucl a lot of times they're just referring to the anterior bundle specifically all right that was a lot of ligaments let's do a quick recap of those ligaments of the elbow joint we have the annular ligament which is connected to the ulna right here wraps around the radius and then connects back to the ulna on the other side as well as the quadrate ligament which is going to connect directly from the radius to the ulna both of those ligaments the annular and quadrate are going to help to hold the radius and the ulna together we also have the oblique cord and the inner osseous membrane which are going to work to keep the radius and the ulna tight together we have course have a joint capsule which is going to wrap around the whole elbow joint to keep in synovial fluid as well as provide some structure to the Joint we have the medial collateral ligament and the lateral collateral ligament so the lateral collateral ligament includes the ulnar LCL which is going to connect the humerus to the ulna as well as the radial LCL which is going to connect the humerus to the radius and that's going to tuck under the annular ligament on the inside we have the medial collateral ligament which has three parts we have the posterior bundle the fan shaped ligament that connects the humerus to the ulna we have the transverse ligament which is going to transverse or cut across all of this as well as the anterior bundle which is going to connect the humerus to this part of the ulna last but not least let's take a look at two muscles that are going to control the movement of the elbow joint now these aren't the only muscles involved in the movement of the elbow joint but they're a really good example of an antagonist pair which are going to sort of work against each other or cause opposite movements in the elbow joint the first is the biceps brachii the biceps brachii starts up here in the scapula or originates in the scapula and then it's going to insert to the radius of the elbow joint right here when you contract the biceps brachii that's going to pull on the radius if you pull on the radius right here connected to the scapula you pull on that it's going to bend the elbow like this when we bend the elbow or reduce the angle of a joint we call that flexion of the joint if you don't know some of those terms I've got a whole video on that which you can check out here or down in the description so the biceps brachii will cause flexion of the elbow joint and we have the triceps brachii which is going to cause extension of the elbow joint extension is whenever you take the angle of the joint and you're increasing that angle the triceps brachii originates in the scapula as well as the top or proximal part of the humerus and it's going to insert into the back of the ulna right here whenever you contract the triceps brachii which runs from here over down to here if you think of shortening that that's going to cause that extension of that elbow joint there an antagonistic pair like I said because they work against each other the biceps break the eye to do this and the triceps brachii to do that and those are two of the primary movers of the elbow joint so that was a lot of terms a lot of structures the elbow joint is a pretty complex joint actually all of our synovial joints are pretty complex but if you want to learn all the stuff the only way to do that is to practice yourself so here is a blank diagram of everything that I just went over take a minute pause the video see if you can identify all of the bones the ligaments and the muscles involved in the elbow joint so those bones include the humerus the radius and the ulna the ligaments include the interosseous membrane the oblique cord both of which are going to hold the radius and the ulna together sort of along the length of the radius in the ulna we have the joint capsule which is going to wrap around the synovial elbow joint we have the annular ligament which is going to connect from the ulna back to the ulna and wrapping around the radius we have the quadrate ligament not pictured here which is going to connect directly between the radius and the ulna right in there we have the lateral collateral ligament which includes three parts we've got the ulnar lateral collateral ligament we have the radial lateral collateral ligament and of course the annular ligament that's all part of the LCL we have the medial collateral ligament which is going to have three parts as well that includes the posterior bundle the transverse ligament and the anterior bundle and two of the muscles that control the elbow joint are the biceps brachii which is going to cause flexion of the elbow as well as the triceps brachii which is going to cause extension of the elbow joint hey thanks for watching and learning about the anatomy of the elbow joint with me quick Insider effect before making this video I didn't know the different parts of the elbow joint so I learned it to make this video and now you can learn it too and I'm going to keep making Anatomy videos so follow along come along for the ride all right catch you next one