The first structural classification is fibrous joints. Fibrous joints, remember, are going to be joints that lack a synovial cavity but are held together by a fibrous material, such as dense regular or dense irregular, usually ligaments of some sort or some sheet of tissue will hold it together. Fibrous joints can be synarthritic or amphiarthritic, and there's going to be three different fibrous joints. your body sutures syndesmosis and interosseous membranes all three of these are held together by a fibrous material which makes them have the commonality of being a fibrous joint so let's start with sutures sutures are found between skull bones and there's lots of different sutures the skull as we see the suture is going to be holding two bones together in the skull and it's going to be made out of dense irregular connective tissue based on the suture being in red what do you think it's functional classification is if you said no movement you're correct but what is that term If you said synarthritic, you are correct again.
Now, sutures in the skull all have very specific names. So the one they're showing you right now is the coronal suture, and the coronal suture runs between the frontal bone and the two parietal bones. That's its main location. Now, in babies, sutures haven't fully formed yet.
There are lots of soft spots. So in babies, there is more movement allowed in the skull, which allows for growth of the brain. Next is syndesmoses. The word syndes means a ligament or a band.
There are two syndesmoses. We find one between the tibia and the fibula at the distal tibiofibular joint. So right here is a little band that actually holds together the tibia and the fibula.
This band is almost like putting a rubber band around a pack of pencils. You get a bundle of pencils, you wrap a rubber band around it, the pencils are now secure together, but you can still wiggle the pencils around. So since syndesmosis between the tibia and fibula is in yellow, what type of movement do you think it allows? If you said some movement, you're correct, and the technical term would be amphiarthritic.
But there's another syndesmosis in your body, and that is... basically your tooth. We call this gonphosis, the very specific name, which is also known as dental alveolar. So let me write that for you.
The word alveolar means socket, the word dental tooth. So your dental alveolar, also known as gonphosis, is tooth and socket. Now why is this considered a fibrous joint?
Because there is a ligament holding the joint together. So the tooth is held in place to the bone by the periodontal ligament. Basically a fibrous piece of tissue holding the tooth in place. Now I want you to think about your teeth. Do they move on their own or are they secure in place?
If you said secure, you're correct. So what about movement? It's in red.
Synarthritic is also correct. Can you manipulate teeth movement? Of course.
That's what orthodontics are all about. Moving the bone by putting pressure on bone to move it around the mouth. So your teeth actually get to move by reshaping bone.
Our last fibrous joint is an interosseous membrane. The word inter is between osseous bone, so we see this membrane between two bones. Now, the interosseous membrane can be found in two spots in the body. Between the shafts, also known as the diaphysis of the tibia and fibula, and between the shafts, also known as the diaphysis between the radius and ulna. This I like to compare to a sheet, a fitted sheet you put on your bed.
Once that fitted sheet is on, it's secure. But can you still move the sheet around? Is the fabric so tight it doesn't budge? If you said no, or yes, I mean no, the fabric's not that tight, so it does give some movement, you're correct.
The interosseous membrane is holding these two bones together in the shaft, both of the radius and ulna. the fibula and tibia and tibia it gives more security and structure to the bone into the joint however it does allow for some wiggle room so this is considered amphiarthritic now remember we also have another fibrous joint in the tibia and fibula right here this joint is called a syndesmosis a band or a ligament that holds two bones together quickly want to go over into Wiley Plus and I want to show you something in here. This is an anatomy overview for fibrous joints in chapter 9. So you can kind of go over it. Fibrous joints are grouped into three structural types. We've got sutures which are found in the skulls.
So we got our compact bone, spongy and more compact and the suture will be found between them. Sutures don't allow movement in adults so this would be thin arthritic. Then we have our syndesmosis. We have ligaments syndesmo that holds the tibia and fibula together.
And then we have our gonphosis, which is basically a tooth in your socket of the bone. This is held together by the periodontal ligament. This is known as a gonphosis again. Both of these are types of syndesmoses.
And last, we have our interosseous membrane that we find between the tibia and fibula, and radius and ulna. The interosseous membrane and the tibia-fibular ligaments are both going to allow some movement, so those are amphiarthritic, while the tooth and the suture should not allow any movement, so those are synarthritic.