Bones of the Upper Limb - Video Tutorials & Practice Problems
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1
concept
Overview of the Arm and Forearm
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Now we're gonna learn how to identify the three bones that make up the arm and the forearm. And we're just gonna jump right in. So we're gonna start with the arm or we often think of as the upper arm. Uh there we have one bone and it is the humerus, the humerus, we are just gonna say, is the large bone of the upper limb. And as we look over at our image here, but we start off, we have the pectoral girdle up here, but in green, we have the humerus there. That's that large bone of the upper limb. And then as we go down, you'll also see we'll have the radius and ulna, which we're gonna go over in a second along with the wrist and the hand bones there just for reference. But as we look at, at, at the, at the humerus there, and I can show you the actual bone here. Well, to me, this is really sort of like very classically bone shaped kind of in my mind's eye. When I think of a bone, I think of the humerus or something like it. But one of the first things that I noticed about it is this real round part on the top that's called the head. And we're just gonna say that that is the round part that fits into the shoulder. And we can see it on our image here, labeled one a remember it fits into the glenoid cavity of the scapula and makes up that ball and socket joint of the shoulder. The other thing I noticed, well, it's got the shaft on it. But then as you go down to the bottom, it gets wider and you can feel the ends of your humerus down there, the elbow on the elbow on the inside and outside, you're touching these parts right here. And that's what sometimes really hurts like heck when you whack your elbow on something. And then finally, there's this real curve part right here that's gonna articulate with the bones of the forearm and we'll check that out in just a second. Ok. So as we look at the forearm, we have two bones and they're roughly equal size. As you can see over here in our image, we have the radius and the ulna. Well, radius here is in orange or, or this orangey red color. And remember we're looking at this in anatomical position. So we're looking hands, uh palms forward, thumbs out. So when we look at it like this, this is the right side of the body, the radius is going to be lateral to the ulna. Now, the way I remember that I'm a little old. So sometimes when something is kind of cool, I say, hey, that's rad. And if you say the radius is rad, you give it a thumbs up. Well, the radius is on the thumb side of the arm. So if I take my radius here, you can see that there's one end is kind of round and one end is a little wider. I lined it up there. So this wider end comes down and is on the side that given the thumbs up this wider end, that's your wrist bone that you can feel right there. I'm gonna say right here, this is the same side as the thumb. And you can see that in our image here, this wide part and here's the thumb. Now, the other really obvious thing about the radius and this is what helps me remember the name is that on the head here, it has this almost perfectly round circle. Well, the name radius, there's a radius is part of a circle. It's the line that goes to the middle of the circle. Well, there's a radius in a circle, there's a circle on the radius. So I say right here circles have a radius and that's how I remember it. This allows you to turn your hand and I'll show you that right now. So as we look at how this fits in the elbow joint, it's only gonna be on the lateral side and it sits on the smooth part right there. And when uh that circle allows that this bone to sort of twist in the elbow joint. And as it does, that you can look down at this thumb side kind of moves in this big circular motion. What's happening there? That's the same thing is when I turn my hand like this, when you turn your hand or, or turn your thumb around your hand like that, what you're doing is you're having the radius spin on that round part that's in the elbow joint. OK? That brings us to the ulna. Now, the ulna, well, if the radius is lateral, then the ulna is going to be medial to the radius. And we can see that in our image here, right? That's sort of towards the midline of the body because that's the right side of the body. It's on the inside. And one way to remember that I don't have it written down here. But you can see here as we look in an ulna, the end of the alma that comes down to your wrist here. Well, it's kind of pointy and the pointy part of the ulna is on the pinky side. So lots of pee there, the pointy ulna on the pinky side, right? That's the medial side. The way I remember the bone though is when you look at the elbow joint where this makes uh joins the elbow, you can see there's a U in the Elma. It makes a U at the Alma oops. And that's where it clamps onto the uh, uh humerus and it makes a hinge with the humerus. So if I take the humerus here, this Ulma just fits on really clearly and really tightly and makes this really clear hinge joint as you bend your arm back and forth. Now I can put the whole joint together, I can take my radius, I take the round part and it fits in, there's a little notch on the ulna where it fits and it fits down there around the other end. And so both of them can do this if you're doing curls and then if I'm gonna turn my hand, this radius will spin and it will actually spin around the ulna. OK. So those are the three bones that make up the arm and the forearm. We're gonna talk more about how we orient them and figure out which side of body they're on. Next. I'll see you there.
2
Problem
Problem
Of the two bones in the forearm, which bone is medial?
A
Humerus.
B
Radius.
C
Ulna.
D
Clavicle.
3
Problem
Problem
When a person falls, a common reaction is to try to catch themselves by sticking out their hands. This will sometimes lead to a fracture in one or both of the bones of the forearm. Because one forearm bone is larger where it articulates with the wrist, this bone tends to absorb more force from the impact and is broken more often, making it the most commonly broken bone in the body. Where would such a break likely occur?
A
The distal end of the ulna.
B
The proximal end of the ulna.
C
The distal end of the radius.
D
The proximal end of the radius.
4
concept
Overview of the Wrist and Hand
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5m
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To finish up the bones of the upper limb. We're gonna be talking about the bones of the wrist and the hand. And we'll start just by saying that the wrists and the hand are gonna be made of three sets of bones. Those three sets are the carpals, the metacarpals and the phalanges. And we can look at our image here, we see the bones of the wrists in the hand. It's a left hand, an anterior view of a left hand. So we're looking at the palm of the left hand because that's what we would be looking at if it's an anatomical position. All right. And in the picture, we can see the carpals here in green, the metacarpals are gonna be in purple and the phalanges, the finger bones are gonna be in blue. All right. So we'll start with the carpal, the carpal, we're just gonna say, are gonna be the eight short bones of the wrist. Now, when you think of your wrist, a lot of times you think of the part where when you bend your hand like this, where it bends at the end of your arm. Well, that's actually a joint between the radius and the ulna and the carpals. Your carpal is kind of start where that wrist bends. And so they really make up a little bit more of the of your hand here. And you can see that if you look at the picture, we have the eight bones in green here. And if you imagine drawing a hand where the actual hand would be on this picture, you can imagine that the hand really sort of comes along and it starts and includes a little bit of those bones of the wrist. They really make up that back of the hand. Now, we're not gonna name the individual carpals here. They do have individual names in a lot of intro anatomy classes. All you need to know is that there are eight carpels. Sometimes you need to know their individual names. If you do, that's just a straight memorization job. It is really unlikely that you have to identify the individual bones by just picking them up and looking at them. That's usually something just for medical school, but like, always know what your professor expects of you. All right, after the carpals, we reach the metacarpals and the metacarpals are going to be the long bones of the palm and the back of the hand and these bones you can feel, feel very clearly. It's each one lines up with a finger. You have 12345 metacarpals and we say the long bones remember, well, when I think of a long bone, I typically think of the bones of my arms and leg. Those are really long bones. These bones aren't nearly as big, but a long bone just means it has that shape of a shaft and two winded ends, the diaphysis and the two epiphysis. And for these metacarpals, this distal epiphysis that or the distals epiphysis are gonna form the knuckles or the first knuckle spell knuckles correctly, uh form that first knuckle where the fingers meet the hand. So I'm talking about right here. Now, when we learn the names of the metacarpals, we don't have individual names for the bones. We just number them based on what finger they are and we just number them starting at the thumb and go straight across to the pinky. So number one is the thumb, 2345 is the pinky finger. So down here, I'm just gonna write one is the thumb or the bone that lines up with the thumb because these are the bones of the hand. And then the fifth one is the bone that lines up with that pinky finger. Ok. After the metacarpal, we have the phalanges, the phalanges we're gonna say are just these 14 tiny long bones. Again, they're long bones, not because they're big, they're really small, but they have the shape of a long bone. And we're gonna say that each finger is gonna have three, they're gonna have a proximal phalanx. Now, before we go any further, that word phalanx, that's the singular of phalanges. A phalanx. That's a Greek battle formation. When people looked at these bones, they thought it, I guess, kind of looked like a phalanx marching into battle. So the first bone is gonna be the proximal phalanx. And that's just your first finger bone here and we can see it labeled uh here three A and this middle finger, the next one. Well, this is the middle finger bone and really original name. It's gonna be the middle phalanx. All right. So proximal middle phalanx and then finally is gonna be the distal phalanx. So if we look here, we have the proximal first bone, the middle one in the middle and the distal phalanx. That's that last finger bone. The only difference between this, that's gonna be true for all uh four of your fingers. The difference is going to be that the thumb only has two, right? You only have two bones in your thumb versus the three bones in your finger. So the thumb doesn't have a middle phalanx. It is only gonna have the proximal and distal. All right, with that. Remember we have eight carpals bones of the wrist. Five metacarpals numbered one through five, starting at the one that lines up with the thumb. Those are the bones of your hand. And then we are gonna have these phalanges, the finger bones proximal middle and distal, but only proximal and distal in the thumb. All right. With that, I'll see you in the next video.
5
example
Bones of the Upper Limb Example 1
Video duration:
1m
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Our example tells us that Sharaa is recently engaged in showing off her ring. Then we want to draw an X on the diagram below where the ring would be placed. And we want to know what is the name of the bone that the ring surrounds. All right. So we're looking at the bones of the hand here. We're looking at the left hand because that's traditionally where an engagement ring goes and again, in anatomical position, remember it's palms forward. So that's what we're looking at. I'm gonna go through here and name all the bones I see until I get to where the ring is placed. Well, first off, we have the radius and the ulna, you don't put an engagement ring there. We have the wrist bones, the carpals, that's not where an engagement ring goes. Now, we're at the bones of the hand. So these are the metacarpals and remember we number them one through five, starting at the thumb. So we have the 1st, 2nd, 3rd, 4th and 5th metacarpal. You don't put a ring there, you put a ring on your phalanges and uh an engagement ring traditionally goes on your fourth phalanx So we're gonna count over 1234. That's your ring finger and the proximal phalanx, that first finger bone is what a ring traditionally surrounds. So the answer to this question, I'm gonna put down as the fourth proximal phalanx. Remember phalanx is singular for phalanges. All right. That's our answer. And congratulations to Sharaa and her fiance.
6
Problem
Problem
Arrange the bones of the upper limb from proximal to distal. Some bones may not be included.
Often people will 'crack' their knuckle by pulling on their pointer finger. The cracking sound comes from knuckle where the finger meets the hand. What's another way to describe this location?
A
Between the first proximal phalanx and the first metacarpal.
B
Between the first and second phalanges of the proximal digit.
C
Between the second proximal phalanx and the second metacarpal.
D
Between proximal and middle phalanges of the second digit.
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