Okay, now we're going to go through the bones of the appendicular skeleton. We're going to start with the upper part. First of all, you've got to have a pectoral girdle, which is going to hold your arms or your appendages in. And so the pectoral girdle...
is going to be made of the clavicle, which is this little S-shaped bone here. It's kind of short and squatty, but it makes an S. And you can see that there's one end of it is really rounded and fat, and then the other end is kind of flattened. and smooshed out.
Well this rounded fat end is the intent, is the end that articulates with the manubrium of your sternum. So that's going to sit up there like that. And then the other end is going to kind of curve around here, and that's going to attach to that acromion process.
I'm going to get this turned around right, like that. And so that's going to form your pectoral girdle. That's one half of the pectoral girdle.
You'll have it going around on the other side with another clavicle and scapula on the other side. side. So that's what your pectoral girdle looks like.
If you want to know if your clavicle is right or left, again, put that fat end up against your manubrium. And then if you look on the curve of the acromial end or the lateral side, you're going to have this little bump. The little bump always goes down and on the back side. So this would be a left clavicle. And that's how you would tell that.
So just look for the bump, put it on the back side. All right. Whoops.
Alright, let's talk about the scapula next. You have two scapula, and first of all, you've got to get it oriented correctly in your body to understand how it works. You've got a smooth side that doesn't have any real processes sticking out on it, and then you've got this side that's got this big, huge process sticking out on it.
Well, this smooth side is what's going to sit right up against your rib cage in the back of your body, so that smooth side can just rotate around those ribs and not get bumped around. This back side is going to be your dorsal. side that has these big processes coming out on that.
So now we know that this is the anterior side because that's the smooth side that is going to articulate with the ribs. Then you've got to look over here. You've got these processes and a little pit here, and that's where your arm hangs out of. And so your humerus bone of your upper arm sits in that little pocket right there.
And so you know this has got to be your lateral side because your arm is not going to hang out of the middle of your body. It's always going to hang out like this. So this would hang out like this.
have to be a right scapula because that smooth side has got to go up against my ribs and then you know the arm has got to hang out on the lateral side. So that's a right scapula. So just make sure you can figure that out. And the key is to put the smooth side interior and then put the lateral side, which has the arm hanging out, to the lateral side.
So it wouldn't work this way because the arm would be hanging down in the middle of my body and that would be kind of creepy. Alright, so let's talk about the different parts of this. First, First of all, if you look at your margins, you know this is the lateral side because that's where the arm is hanging out. So that's going to make this straight side right here your lateral margin.
If that's the lateral margin, then that has to be the medial margin because it's going to be sitting in your body like this. This is lateral, this is medial. You've got a bunch of processes coming up. On the back side or the posterior surface or dorsal surface, you've got this big spine coming up and that's called your dorsal or spinous process.
So what we're going to do is we're going to go ahead and do a little bit of a covered. The spine. The spine, yeah.
The spine on the dorsal surface, okay. And then that spine kind of flattens out up here and that forms what we call the acromion process. Well if you remember, your shoulder is the acromial region of your body. So this is going to sit right up in here like this and that's what's going to make the shoulder is that little process right there. So when you feel your shoulder bone right there, that's what you're feeling, that acromion process.
And again, this is going to be an attachment point for muscles. And coming. From that way, you've got this little pocket right here that your arm is going to sit, or your humerus of your arm is going to rotate around in. That's known as your glenoid fossa or glenoid cavity. And then coming in front of that, we're back to the anterior side, you've got this little hook process right here.
That's called the coracoid, not coranoid. We've heard coranoid process, but this is coracoid process. And that's where your biceps muscles from your arm have an attachment point there.
So you've got your anterior surface is smooth, your dorsal surface has the spine on it, the spine comes up and makes that flattened acromion process which makes your shoulder. Then you've got the glenoid cavity or glenoid fossa that your humerus bone attaches to and then you've got this curved or hooked process right there. called the coracoid process that your biceps muscles attach to. Then you've got your medial margin over here and then you can always figure out right and left if you get your anterior surface in the front.
and then put your, where your arm goes to the lateral side and that'll tell you right away what you have. So that's your scapula. Alright, the next bone you have would be your humerus bone, so that's going to sit right here. Now you've got to figure out if you have a right or left humerus. Well, it's easy.
You know, I've already shown you that this ball part of the humerus is going to be the proximal end, which is going to attach to the body. So it attaches right there in that glenoid fossa. So you know this is the proximal end, and that makes this the distal end.
So we've got it sitting right, so it's kind of oriented in our body, right? But does it go like this, or does it go like this? I mean, you could put the ball this way or this way.
Well, you go down to the distal end, and you look, and you see there's a large cavity at the distal end. in on one side and there's just a smaller tiny cavity on the other side. So when you're trying to figure out what you have, put that large cavity in the back. So the ball is going to be proximal or towards the top and then you put that large cavity towards the back and that's how it's going to sit in your body.
So that makes this a right humerus. Okay, now let's start naming some of the parts. We've already talked about this right here.
That's the ball or the head of your humerus. It's and that's of course what articulates in this glenoid cavity to hold your arm to your body. And then you've got going, if you go down, if you just follow this down, remember this is going to be the medial side that your ball is attached to. It's closer to the midline. Okay, so this is all going to be your medial side.
Well, if you go straight down your medial side, you're going to come across this little thing right here on the end that kind of looks like a spool of thread. Just ignore it. this right now and just kind of look like that little thing right there it looks like a spool of thread well that's known as the trochlea it's also known as the medial condyle remember a condyle is a rocker so something's going to start rocking on that what turns out it's your ulna which makes your elbow joint right there we'll come back to that in a minute but that rocks right there on that trochlear process so this trochlea right here just this little spool of thread is actually your medial condyle. Then if you go down on the lateral surface of the bone, you come down to this little, looks like a bald head right there, that's going to be your lateral condyle, but that's known as the capitulum.
So you have the trochlea and the capitulum. The capitulum is again an articular surface for the other bone in your lower arm, which is your radius, so that we'll just sit there and rock around on that like that. So these are two of your articular surfaces for your lower arm bones. So on the medial side, coming down this way, you're going to have the trochlea.
On the lateral side, coming down this way, you're going to have the capitulum. Capitulum actually means bald head. And you think about somebody being decapitated, think capitulum, capitation, that reminds you of that head there.
Okay? Well if this is the lateral condyle, the capitulum, then that makes this little bump right here the way. lateral epicondyle.
Epi means above or upon, so that's the condyle above the condyle. So there's your lateral condyle, the capitulum, and then there's the epicondyle, that little bump above it. And then on the medial side, you've got the medial condyle, which is the trochlea, but then you've got this medial epicondyle, which sits above the trochlea, or above the medial condyle. And I think that's, oh okay, and then you have your fossa. that you have to know.
You've got this ulnar bone is going to come around here and you've got two articulation points where you need to stop it. So this fossa in the front or anterior side of the bone is going to be known as your ulnar bone. coronoid fossa.
I just went blank there for a minute. So that's your coronoid fossa right there and that makes this of the ulna, we'll come back to that, your coronoid process. Then if you look on the posterior side of the bone where you have that big cavity there, that's no known as your olecranon fossa. And then you have the olecranon process, this large process right here, which is going to go around and articulate with that olecranon fossa. So you have the olecranon process going into the olecranon fossa.
That's what you feel as your elbow bone right there. So if you're sitting there with your arm on the desk like I am, it's like that, where you're sitting right there, and that's your elbow. Okay?
We'll come back to it. Some more of this in just a minute. Let's go to the next bone then, which is the ulna.
And if you look at a, well that poor skeleton doesn't have an arm, but if you look at a skeleton, you're going to have your humerus, and then you're going to have your trochlea, I mean your ulna attached to it, and then you're also going to have your radius attached to it like this. I can't get them all in there together. It goes something like that.
So you've got these two bones here, and you've got to remember, well which one is which? Okay, I know I've got my hand coming down. down here, and which one is which?
Well, remember, in the anatomical position, you're going to have your arms like this, okay? That's the correct anatomical position. So the ulna, or the bone with the U in it, is under. So it's going to be the one on the lower part, and that's going to go down towards your pinky.
And then your radius is the other bone, and you can always recognize the radius, because if you look at the end of it, it has this nice perfect circle here. Remember your math equations talking about... about pi r squared and all that kind of stuff where you use radius to define a circle. Well, there's your circle right there.
So this is the radius. And the radius, if you look on your arm, your radius makes an r. So your radius comes down and you can make an r right there with your arm. So your ulna is going to be on this lateral side. Well, it's medial side when you're in an anatomical position.
And then the radius makes the r. So that's how you kind of keep them separated and know which one's... going where. Alright, let's talk about the parts of the ulna first.
The head of the ulna is actually the distal part of the ulna. And I know that doesn't make sense and I don't know what kind of crack those anatomists were smoking when they named it, but that's just the way it is. So the distal part, see this is the proximal part that's attached to the humerus, but the distal part here we call the head of the ulna.
And the only thing you need to know on that is this styloid process. here, that pointy process that looks like a pin, and that again is another attachment point for muscles. So that's the head of the ulna.
Then where you have this U here, that's on the proximal end, and that's what articulates on this trochlea here, and you've got the olecranon process that goes in here to the olecranon fossa. Let me turn it so you can see it. Okay, so the olecranon...
process goes into the olecranon fossa then you have the trochlear notch that actually rides on the trochlea that spool of thread right there and then you've got the coronoid process right there that goes into the coronoid fossa up here on the anterior surface so there's your coronoid fossa there so that's all the parts of the ulna then you have your radius and the only thing you need to know on the radius is the head, and that's that rounded end there that makes the perfect circle, and then you have this big bump on it known as your radial tuberosity. The proximal end. It's at the proximal end because this would be at your... Distal end, I can figure out proximal and distal, okay? So the proximal end is going to have the head, which is the opposite of the ulna.
The ulna, the distal end is the head, but on the radius and most other things, the proximal end is going to be the head. So this is kind of the exception here, the ulna. So just know your head and then your radial tuberosity, that big bump right there.
And that's all you need to know on your radius.