Bone of the Lower Limb - Video Tutorials & Practice Problems
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1
concept
Bones of the Thigh and Leg
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4m
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Video transcript
Now we're gonna talk about the bones of the thigh and the leg. Specifically, we're gonna talk about the femur, the patella, the tibia, and the fibula. Before we get going, though, let's just orient ourselves to our picture here. We're looking at an anterior or a frontal view of the right leg, and we see the fore bones that we're gonna talk about all color coded. And then we also just see the pelvis or just the pelvic girdle right there and the bones of the ankle and the foot there at the bottom, just for reference. Right. We're gonna start off by talking about the femur. The femur, we're gonna say, is gonna be the strongest and the largest long bone in the body, and we can see it's right in green here. Now this bone, the femur, it's a big old honking bone. Right? It's really noticeable as the largest long bone, and the other thing that's really noticeable about it is this round head on it. In our picture, we have this round head right up here labeled as 1 a, 1 a. This round head, we're going to say is going to be the round ball that fits into the acetabulum. So here's my coxal bone, and we did this in a previous video, but these 2 fit together just so clearly to make that ball and socket joint. The head of the femur is that round ball. Now as we look down the other end of the femur, well, this epiphysis, this is going to make up the knee joint, and it's gonna articulate with 2 bones there, the patella and the tibia. So first, let's look at the patella. The patella, well, that's purple in our diagram over here, and it's gonna be a sesamoid bone, we're gonna say. Remember, sesamoid bone, that is a bone that develops entirely within a tendon and the patella develops within the patellar tendon. That's the tendon that runs from the quad down to the tibia over your knee. Now the patella, if you remember when we learned parts of the body, patella comes from the Latin meaning a small dish, and this bone is just kind of well, it's just kind of this flattish, relatively roundish bone, so you can imagine it kind of looking like a really small teacup saucer or something like that. Now you probably just know your your patella as your kneecap. And if you go down and you feel your kneecap, you move it around a bit, what you're touching there, what you're floating around, you're floating around the patella in that patellar tendon. Okay. The other bone that makes up your knee, the tibia. The tibia is gonna be the larger, more medial bone of the lower leg, and we can see it in our image here in orange. That's gonna be the tibia. So it's gonna articulate and make up the knee here. So we're gonna say just that this contributes to the knee joint, and we really call that out because that's gonna be different from the fibula. The fibula does not articulate with the femur. It does not make up part of the knee. That's different than your upper arm. Right? In your upper arm, your forearm, both bones articulate with the humerus to make the elbow. In your lower leg, only one bone, only that one bone of the lower leg, the tibia, articulates into that knee joint. Now other things that you just might notice about the tibia, it has this real sharp front on it. That's that shin. Right? Your shin, if you ever whack your shin on stuff, you're whacking that part of the bone right there, hurts like heck. The other thing you'll just notice, it's a little bit longer on one end than the other. It comes down a little bit farther here. That's your inside ankle bone. It's also called your medial malleolus. Your inside ankle bone, that's another thing that sometimes you whack on stuff. So your tibia, you often whack it on things. Alright. The other bone of the lower leg is gonna be the fibula, and the fibula is this bone that we see here in blue on the on the outer side of the leg there. So it's on the outer side of the leg, so we are gonna say it is the smaller oops. The smaller, more lateral bone. Right? Now, you can't really feel the the fibula as well as you can the tibia. The only place that you really can feel it is down in your ankle, what's called your lateral malleolus, is this part of the the fibula down at the end. That's your outer ankle bone. The rest of it sorta articulates well at the top. It articulates with the tibia, and the rest of it sort of inside the muscle that you can't feel that well. Now the way I remember the tibia and the fibula, because those words, a lot of times, people get them switched around their in their mind, The tibia is tough. This is a big old heavy bone. The fibula is fine. The fibula is this kinda narrow, light looking bone. So again, the tibia is tough. The fibula is fine. Alright. We're gonna talk about about all these bones a little bit more going forward. I'll see you there.
2
example
Bone of the Lower Limb Example 1
Video duration:
2m
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Video transcript
Our example tells us that you forgot your shin guards at soccer practice and managed to get kicked in the shin, the inner ankle, and the outer ankle. Yowchers. Alright. Which bone is getting kicked in each scenario? K. To help us out, we have a picture here of the lower leg. We have an anterior view of the bones of the lower leg starting at the patella all the way through the toes. And so this is going to be the left leg that we're looking at, and we want to know what bone makes up the shin. So what bone is the shin? Well, as I look at this picture, the shin is this bigger, heavier bone right here. The front of that bone is what you get kicked in when you get kicked in the shin, and remember the bones of those lower legs, that's the tibia tibia and the fibula, and the tibia is tough. The fibula is fine. So that bigger, tougher, heavier bone, that's that's gonna be the tibia, specifically the anterior border of the tibia. Alright. So then which bone makes up your inner ankle bone? Well, again, as I look at this, the inner ankle bone so that medial side here is gonna be right here. That's that inner ankle bone, and that's the same bone. This is part of the tibia. So the tibia is makes up the inner ankle bone. There. Now I'm gonna get a little bit more specific here. I'm just gonna say you if you wanna get really specific, you could say that that is the medial malleolus of the tibia. The malleolus is another name for the ankle bone. Alright. So then what bone makes up the outer ankle bone? Well, as I look at the picture, here's the outer ankle bone there. So what is that part of? Well, it's part of this thin bone here, the more lateral bone. And remember the thin bone, that's a finer bone. The tibia is tough. The fibula is fine. So this is gonna be the fibula. And again, if I wanted to get really Oh, just spelled fibula there. If I want to get more specific, I could say that that is going to be the lateral malleolus of the fibula. Alright. That's the answer to our question. More problems to follow, where are your shin guards?
3
Problem
Problem
With which bones does the femur articulate?
A
The tibia, the fibula, the coxal bone, and the patella.
B
The tibia, the coxal bone, and the patella.
C
The tibia, and the coxal bone.
D
The tibia, the fibula, and the coxal bone.
4
Problem
Problem
The structure of the upper limbs (the arms) and the lower limbs (the legs) follow a similar pattern. Which of the following statements comparing the limbs is not accurate?
A
Between the girdle and the wrist/ankle, the lower limbs have more bones.
B
The radius and ulna bear weight roughly equally, where the tibia bears much more weight than the fibula.
C
The humerus articulates with both bones of the forearm at the elbow, while the femur only articulates with one bone of the lower leg.
D
The radius and ulna have less mobility between them than the tibia and fibula.
5
concept
Bones of the Foot
Video duration:
5m
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Video transcript
To finish up our bones of the lower limb, we're gonna talk about the bones of the foot. Now the foot and then the ankle is made up of 3 sections of bones. And if you remember, that's just like the hand. In the hand, we have the carpals, the metacarpals, and the phalanges. In the foot, we have the tarsals, the metatarsals, and again, the phalanges. The toe bones and the finger bones have the same names. Alright. Before we go into these, let's just look at our picture here. We have a top down view of the bones of the foot. We're looking at a right foot, and in green here, we can see the tarsals, in purple, the metatarsals, and in blue, we see the phalanges. This is gonna be the big toe, the pinky toe, and the heel back there. Alright. So the tarsals, we're just gonna start off by saying these are the 7 short bones of the ankle. But we can liken this to the carpals. Right? Remember, there's 7 tarsals. There's 8 carpals. Sometimes people get those numbers switched. So 7 tarsals. But just like the the carpals we said are really sorta more the bones of the back of the hand, well, that's even more so for the tarsals. These tarsals you can see in this picture here, they really make up a lot of the back of the foot. And what you think of as your ankle, probably, where your long bones of the lower leg meet your foot, that's gonna be the joint in this first bone here that we've labeled 1a. Now like the carpals, you don't need to know the name of every tarsal, but you likely do need to know the bone the name of this bone and one more bone that will go on over in a second. So this first bone where that tibia joins the ankle is called the talus, and you can see it here in my model foot here. It's just this real smooth round bone on top of all the other tarsals. So we're gonna call this the talus, and we say the talus is the top of the ankle, and the talus is the top of the tarsals. Right? So when you look at all your tarsals, this round smooth one on top, that's the talus. And the reason it's round and smooth like that is you can take the tibia and articulate it there in the ankle. And as you point or flex your toe, that talus is just gonna sort of rock or hinge back and forth in that tibia. You'll see it also has a smooth section on the side. The fibula also articulates with that talus. Alright. The other tarsal you're likely to need to know is going to be the calcaneus. The calcaneus, that's labeled 1 b right here. This is your heel bone, and you can see it's sort of in this picture, it's sort of sticking out the back, but it's the biggest tarsal, and it's really noticeable if you look at the foot. Making up almost, like, half or more than half the length of the tarsals is this calcaneus. The heel bone sticks out in the back. If you have to ever have to identify it individually, it's just this really kinda lumpy weird bone. But in the foot, the heel bone calcaneus is very noticeable. Alright. After the tarsals, we get to the metatarsals. The metatarsals are gonna be the long bones, and these are gonna create the arches of your foot along with some of the tarsals. Alright. You have that arch in your foot. That really helps you distribute weight along your foot, and the metatarsals are doing a lot of that job. Now these are gonna be just like the metacarpals in the hand. There's 5 of them. 1 lines up with each toe. We're gonna number them 1 through 5. The most medial one is gonna be numbered 1. The most lateral one is gonna be numbered 5. So this medial 11 is gonna line up with your big toe, and this lateral 15 is gonna line up with your pinky toe. Alright. That brings us to the phalange. The phalanges, just like the finger bones, are gonna be these 14 tiny long bones. And, again, remember, long bones talks about the shape and how they grow, not about how big they are. This long bone right here at the tip of your toe, pinky toe, that's a really small bone, but it's still a long bone. Alright. The singular of phalanges, remember, is a phalanx, and that just comes from that word that means that Greek battle formation. And, again, just like the fingers, each toe is gonna have 3 phalanges, a proximal, middle, and distal. And we can see that label on the second toe here. A is gonna be the proximal, then we have the middle, and c will be that distal phalanx. That's gonna be different for the big toe. So the big toe is only gonna have 2. It does not have a middle phalanx, and we can see that here. It just has the proximal and distal. Remember, that's just like the thumb, only 2 bones in the thumb, only 2 bones in the big toe. Alright. That's the foot. Practice more going forward. I'll see you there.
6
example
Bone of the Lower Limb Example 2
Video duration:
1m
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Video transcript
Our example says that if you have 5 toes and proximal, middle, and distal phalanges, well, 5 times 3 equals 15, Then why do you have only 14 phalanges? And to finish the question, I should probably say on each foot. But regardless, let's take a look. I'm going to start out just by well, we have a picture of a foot here showing all the bones. I'm going to start by crossing out everything that isn't a phalanx. So that line is where your toes start. Now I'm crossing out the metatarsals. Now I'm crossing out the tarsals. So if we look at our phalanges here, I'm going to label the proximal, middle, and distal phalanx on that second toe. Well, what's the key to this question? Why don't you have 15? Well, the key is the big toe. Right? The big toe only has a proximal and distal. There is no middle phalanx on the big toe. So I'll write that out. No middle phalanx on big toe. We can also call the big toe the hallux if we're feeling fancy. All right. That's, of course, also true for the thumbs. Remember that we answered a question.
7
Problem
Problem
How do the metatarsals contribute to the foot's ability to bear weight?
A
Their irregular shape helps them distribute the weight of the body.
B
The seven bones distribute the weight, so each bone only withstands a fraction of the total body weight.
C
The bones have additional collagen to help them resist force and twisting.
D
The bones help create arches that distribute the weight.
8
Problem
Problem
Distinguish between the Talus and the Calcaneus.
A
The talus is considered one of the tarsals; the calcaneus is not.
B
The talus articulates with the tibia; the calcaneus only articulates with other tarsals.
C
The calcaneus is the heel bone; the talus makes up the parts of your ankle bones that you can feel.
D
The calcaneus is the largest tarsal; the talus is the smallest tarsal.
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