This is a tutorial on the general skeleton. I won’t be going into a lot of detail about each individual bone and all their features. If you want to learn a bit more about that, then have a look at some of my other tutorials.
The skeleton has both fused and individual bones. It acts basically as a framework for muscles to attach to and it also protects and supports organs such as the heart, lungs and brain. Bones are connected at joints by ligaments (which on this model here are these little white things) and muscles would attach to bones by tendons. You’ve also got cartilage, which could be found between various joints.
The skeleton can be thought of as – well, it’s broken into an axial and appendicular skeleton. The axial skeleton consists of the bones along the central axis of the human body.
There are six bones which make up – well, not six bones, but six things that you need to remember that make up the axial skeleton. You’ve got the skull, the ossicles (which are little bones in the middle ear), the hyoid bone, the rib cage, the sternum and the vertebral column. I’ll just quickly show you those.
These bones make up the axial skeleton, which is the central axis of the human skeleton. The first bone is the skull (which you probably don’t need to be told), the ossicles actually aren’t on this model, but they’re little, tiny bones in the middle ear, this bone in the throat is the hyoid bone [00:01:55], then the sternum here and the rib cage (which is this set of ribs) and then the vertebral column. That’s the axial skeleton. As you can see, it’s central.
The appendicular skeleton as you can probably guess comes from the word ‘appendage’, so that basically means something that’s attached onto something else. It’s essentially all the rest of the bones that aren’t on the axial skeleton – so all your limbs. The appendicular skeleton is involved with movement.
You’ve got the appendicular skeleton and the axial skeleton. When you come across those words, you’ll hopefully what they mean.
Just to begin with, we’ll start going through the bones of the body. I’ll start at the top and work my way down. We’ve got the skull here. The skull consists of the cranium, which is this. That, in itself consists of many different bones, but we’ll look at those in another tutorial. And then you’ve got the mandible. The skull consists of the cranium and the mandible.
Next, you’ve got the vertebral column, which extends right from the base of the skull here all the way down to meet the pelvis. On the vertebral column, we’ve got 24 articulating vertebra, which are these little bones, individual bones. And then at the end of all of them, you’ve got the sacrum and you’ve got the coccyx. The sacrum and the coccyx consist of fused bones.
Within the vertebra, the first seven vertebra are the cervical vertebra. And then you’ve got the next 12, which are in the chest region and these vertebrae articulates with the ribs. These are known as the thoracic vertebra. And then you’ve got the lumbar vertebra, five lumbar vertebrae in the lower back region. You’ve got seven cervical, 12 thoracic and five lumbar vertebra.
I’ve already shown you the hyoid bone here. I’ve spoken about the ossicles. The next part of the axial skeleton is the sternum, this central bone here otherwise known as the breastbone. There’s three parts to the sternum. It doesn’t have them labeled, but the first part here is the manubrium and then you’ve got the body of the sternum here and then this is the xiphoid process or the xiphisternum. That’s the breastbone.
This little joint here between the manubrium and the body of the sternum is known as the angle of Louis or the sternal angle. It’s quite important to know this. This is an important anatomical landmark because this is where the second rib joins. When you’re doing physical examination on patients or something, you can use this landmark because you know it’s the second rib. if you were looking for the apex beat for instance, which you know is in the 5th intercostal space, mid-clavicular line, you can feel for this little angle here, the angle of Louis and then it’s three intercostal spaces down and then in the mid-clavicular line.
Let’s bring in the heart. You know this is the second intercostal space because it’s after the angle of Louis and then you just count down to the fifth intercostal space and you can find what you’re looking for.
That’s that. That’s the sternum.
And then you’ve got the ribs here, which is part of the axial skeleton. You have got 12 pairs of ribs, so 24 ribs. And then these 12 ribs get broken down into true and false ribs. You’ve got seven true ribs and five false ribs.
These things are the costal cartilages. They link the ribs to the sternum. The true ribs, the first seven ribs are the ribs which have their own costal cartilage. One, two, three, four, five, six, seven. They’ve got their own costal cartilages. And then you’ve got five false ribs. These next three ribs have a common costal cartilage. They don’t have their own one, so they’re false ribs. And then you’ve got these two little ribs below that, the 11th and 12th ribs, which are known as floating ribs because they don’t even have a costal cartilage. They don’t connect to the sternum. They only attach to the vertebra.
You’ve got 12 pairs of ribs. Of those 12 pairs, you’ve got seven true ribs, five false ribs and of those five ribs, you’ve got two floating ribs.
That’s the axial skeleton that I’ve just covered. Now I’ll just talk about the appendicular skeleton and show you the bones of that.
Just starting from the top, we’ve got these two bones here, which are the clavicles. We may know them as the collar bones. You can see this on yourself and you can feel them on yourself. If I just show you that, you can see that little indentation, which is the clavicle or where the clavicle lies.
And then you’ve got your upper limbs. You’ve got your upper arm, your forearm and then your hand. The bones of the upper arm are known as the humerus. This bone here is the humerus. And then the lower arm, you’ve got the radius and ulna. The ulna is the bone which is medial in the anatomical position. The radius is lateral in the anatomical position. These are the two bones of the lower arm.
And then in the hand, you’ve got quite a lot of bones. You’ve got the carpals. You’ve got eight carpal bones, which I’ll do a tutorial on, a separate tutorial on. You’ve got the metacarpals and you’ve got the phalanges, which are the fingers, the digits. If I just show you that, you can see that you’ve got three phalanges here and the metacarpal and carpal bones. That’s the bones of the upper limb.
And if I just rotate this around, you can see this bone here, which is the scapula. This articulates with the humerus. You’ll be able to feel this on yourself again. It’s often referred to as the shoulder blade. That’s the scapula.
Working our way down, now we’ve got the pelvis here. The pelvis consists of the pelvic girdle, which is these big two hip bones and then you’ve got the pelvic region of the spine, the sacrum and the coccyx. That’s the pelvis.
These pelvic bones are known as the coxa. They consist of three fused bones. You’ve got the ilium, the ischium and the pubis. Each hip bone or coxa consists of three fused bones – ilium, ischium and pubis.
That’s the pelvis.
And then coming down to the lower limb, you’ve got the leg. You’ve got the thigh, the lower leg and the foot. This big bone here is known as the femur and it’s the largest bone in the body. And in the lower leg, you’ve got the tibia and the fibula. The fibula is lateral. You can feel this little bit here, the head of the fibula on yourself. It’s that little bump on the outside of your leg just next to your knee. If we have a look there, you can see where it lies just here. You’ve got the tibia and fibula.
And in the foot, like in the hand, you’ve got carpal bones, in the foot, you’ve got tarsals. In the foot, you’ve got seven tarsal bones. Again, I’ll cover these in more detail in another tutorial. And then you’ve got the metacarpals and the phalanges, which are your toes. You could see that.
And then you’ve got the patella, which is your kneecap here.
I think that covers the general skeleton. I hope you’ve got a good understanding of it now. If you want more detailed tutorials on the individual bones and the different features, then I’ll be doing a few soon. Check back and have a look out for those.