Right as we go through this second section, we're going to talk about how bone fractures are repaired and what different types of fractures you can have. So really there's four different steps that occur in three phases for bone repair. The first one is basically an inflammatory phase.
It's a reactive phase where you form a hematoma around a bone break. Now, this is why if you've ever broken a bone and you went to the ER and they put a splint on it and you had to come back a day or two later to get a cast or go see your orthopedic guy to get a cast on. That's because in this inflammatory phase, there's a lot of swelling going on because that's what inflammation is. And so if you put a cast on early on, you could continue to swell, in which case you would cut off circulation to the where the arm or the leg that you put the cast on, which could be a. big problem.
Or if it's still inflamed, but not getting bigger as the inflammation goes down, then the cast is too big and it's not going to be effective at holding your bone in place. So they're going to wait until this inflammatory stage, the swelling has stopped before they're going to put a cast or a permanent cast, well, semi-permanent cast on a bone. Then you go into the reparative phase, which is two steps.
First, you're going to form a fibrocartilaginous callus. So a callus is basically where the cartilage comes in and fills in the space. And then that's going to be followed by a bony callus.
So bone will replace the cartilage in much the same way that you have endochondrial bone formation. And then finally, you get a healed fracture. Now notice you have a little bulge here. You get what's... kind of like a scar tissue forming here on your bone.
So you can look at an x-ray and see a fracture easily. But eventually that bony callus is going to be remodeled and replaced with mature bones. So if you look at this bony callus here, you can see the end is not compact bone. It's still cartilage here. So that's going to be remodeled so that the edges become compact bone as they should.
Now, the types of fractures you can have, and you can have more than one type at a time. For example, you have open and closed fractures. Closed fractures just mean it's a broken bone, but it doesn't penetrate the skin. With an open fracture, the edge of the bone is actually protruding out through the skin, which creates an infection issue. So that can be a big problem.
And these are almost always going to require surgery to be repaired. Um, so you can have other types of fractures we're going to talk about, and those could be open or closed. Then you have common uter fracture. That's where the bone is basically broken into several pieces like right here. So that could be like an impact injury.
Uh, green stick fractures are common in children, particularly in the arms. Um, and that's where you have an incomplete fracture where the bone is actually bent, but the. fracture doesn't go all the way through the bone and that's called a green stick.
And you'll see that the lower leg here, you see you have two bones. When the arm, you also have the two bones. And we're going to talk about this next unit with axial skeleton, axial and appendicular skeleton.
But on the appendicular skeleton in the lower leg, in the lower arm, you actually have two bones together. So it's not uncommon for like this bone to completely break and this one to partially break like a green stick. And that happens in the forearm of children very often. And that's because their bones are not fully calcified.
So they are a little bit more flexible than you see in adults. So they don't necessarily always break. They have the ability to bend a bit.
And then an impactive fracture, that's also known as a buckle fracture. But those can be impact fractures as well. Like say you fell off a roof and landed on your feet and this bone is driven, it broke.
And then this... end is driven down into this end, or this one is driven upward this way. Transverse fractures are called complete fractures, and that's where the break runs perpendicular to the shaft of the bone, and that's what you see here.
You can also have spiral fractures or twisting fractures. These are actually common in, or not common, but you can see them in children who've been physically abused. where their arms have been twisted. There's very few occasions where that would happen naturally. Maybe if you fell off a roof or out of a tree and you grabbed the limb and as you held on to it, you were spinning around, that could do it.
But it would take something like that to create a spiral fracture. So usually it's involved with an adult or some large... bigger human intentionally twisting an extremity, but you get this spiraling fracture that wraps around the bone like a corkscrew. Then you can have oblique fractures, and that just means that it's broken at an angle.
Happens and falls a lot in motor vehicle accidents. Not ankle, angle, that's a typo on my part, but it's broken at an angle. Then you can have these special fractures. A pot fracture is where you actually break the end of the fibula. The fibula is the small bone in the lower leg and it wraps around the side of the ankle.
So if you break that, so when you're looking at your ankle, you're actually seeing this bump here on the fibula and the tibia, the actual leg bones are what create those bumps on your ankle. But if you break that off, it's called a pot fracture. And that's called the lateral malleolus here. A collis fracture is basically when you do the same thing on the wrist, where you break off the edge of the radius at the hand.