Full transcript
0:00This is the last video over Chapter 7. We're going to be looking at bone disorders.
0:07A stress fracture is a break caused by abnormal trauma like for instance being in a car accident.
0:16A pathological fracture is a break in the bone that's been weakened by disease such as cancer
0:23or osteoporosis. Fractures can be classified by being displaced versus non-displaced. Displaced
0:34means that the ends of the broken bone are out of place so you actually have to manipulate it and
0:41put it back in alignment. Non-displaced means they're still aligned together. "Open" versus
0:47"closed" is the new terminology for "simple" and "compound". "Open" means you have broken through
0:55the skin. "Closed" means you have not. When we look at these X-rays, this is non-displaced. You
1:04can see that the bones are still lined up very nicely. This is displaced. This one is going
1:09to have to be manipulated and lined up again. Comminuted is where there are multiple breaks.
1:16Greenstick is usually seen in children. This is where the bone is bent on one side and broken on
1:25the other. They have more collagen fibers and their bones are a little bit more flexible.
1:32When we heal fractures, there's a certain process that occurs. The first thing is once you break
1:40the bone, you are going to form a hematoma - this is a blood clot. Once you have formed a hematoma,
1:48this is going to be converted to a soft callus. This is fibrocartilage. You will have lots of
1:56collagen fibers in this. That soft callus is then going to be converted to a hard callus - which
2:04is spongy bone. That spongy bone will then slowly be remodeled and you get compact bone.
2:14A closed reduction is where you have a procedure in which
2:19the bone fragments are manipulated into their normal position without surgery.
2:24Open (reduction) - this is where you need surgery - usually plates, screws, pins.
2:31A cast, of course, is used to stabilize and immobilize that bone until it heals. Here is
2:39looking at an open reduction on an ankle fracture. You can see the plates and the screws on this.
2:48Osteoporosis is the most common bone disease. It affects mostly the spongy bone. Where you see most
2:57of the fractures due to osteoporosis is going to be in the hip, the wrist, and the vertebral
3:04column. In the vertebral column, the vertebra can actually collapse down due to the lack of calcium
3:12in the bone. This can cause hyperkyphosis which is an exaggerated curvature of the thoracic region.
3:24Some of the complications due to this hyperkyphosis are pneumonia and thrombosis.
3:32Estrogen helps maintain your bone density in both sexes. What it does, it inhibits those
3:40osteoclasts. So who is at the greatest risk is going to be post-menopausal white women.
3:48We do see osteoporosis in young female athletes that have a very low body fat.
3:56That low body fat causes them to stop ovulating and that decreases their estrogen blood levels.
4:06There are a number of treatments. One is estrogen replacement therapy. We have
4:12medications that destroy osteoclasts but the best treatment is prevention. So while you are young,
4:20exercise and build up your skeleton and so this prevents bone loss later on in life.
4:31If we look at some figures here - on the left hand side is spongy bone that is nice
4:37and healthy. You got good calcium in here. On the right side is osteoporosis. You have lost calcium;
4:47you have lost trabeculae. This is very likely to collapse. If we look at this image,
4:55you can see this vertebra has collapsed down because of the weak spongy bone inside.
5:04This is the end of Chapter 7. The next chapter is the Skeletal System.