Fractures (pages 194 - 195)
 | Types of fractures
 | Due to injury, called traumatic fracture, or due to disease, called pathologic
(or spontaneous) fracture. |
| A fracture that pierces through the skin so that it is open with the environment and no
longer protected by the skin from infection is an open fracture. A
fracture that does not pierce through the skin is a closed fracture. |
| Your book outlines 6 different specific types of fractures. Transverse and oblique
fractures should be easy to remember, since you already know about transverse and oblique
sections. The others take a little bit of perusal...
- transverse fracture-- a break in a cross-sectional plane
- oblique fracture-- a break at an angle to the long axis of the bone
- spiral fracture-- this is more about how it occurred than how it looks afterward...
twisting has other clinical implications (and it kind of looks like an oblique fracture)
- fissured fracture-- an incomplete break in the plane of the long axis of the bone (it
would be near impossible to really have a break all the way along the longitudinal plane).
- greenstick fracture-- this is an incomplete break, only on one side of the bone.
- comminuted fracture-- this is the worst kind of fracture because it is a shattering of
the bone into many pieces (some of which may never be recovered usably)
|
| Body Online diagrams the types of
fractures and also shows how screws or plates may be inserted. Go to the main page,
link to "Skeletal System," scroll down to the bottom and select "Broken
Bones." |
|
| Steps to recovery
| Because bone is so highly vascularized, bleeding, even if it all
remains internal, occurs. |
| A blood clot forms |
| osteoblasts are generated in large number |
| osteoclasts and phagocytic cells (like macrophages) come in and clear
out bone fragments and blood clot debris, respectively. |
| fibroblasts invade the damaged area between the edges of broken bone
and lay down fibrocartilage... this fibrocartilage plug is called a cartilaginous
callus. |
| fibrocartilage is replaced by bone (chondrocytes die and osteoblasts invade), replacing
the cartilaginous callus with a bony callus. |
| final touches to the bony callus are made by osteoclasts and osteoblasts-- then repair
is complete! |
|
| Fractures across the epiphyseal disk in children
| Children require their epiphyseal disks to be normal in order for their bones to
lengthen. |
| If a fracture occurs across an epiphyseal disk, the fracture line will end up replaced
by bone... and that means that a piece of the epiphyseal disk is no longer cartilage. |
| A break across the epiphyseal disk in children can thus prevent normal bone growth. |
| Luckily, the weakest part of a normal bone is along the diaphysis, so that breaks across
epiphyseal disks are rare. |
|
Osteoporosis (page 198)
Osteoporosis is a disease where too much hydroxyapatite is removed
from bone. This can happen in the elderly, and it can also happen in conditions
where the parathyroid (which secretes parathyroid hormone) or thyroid (which secretes
calcitonin) glands are abnormal in function. In these cases, homeostasis of bone
inorganic salts is not fully possible, and calcium leaks out of the bone. Since the
calcium salt gives the weight and strength to the bone, the bone becomes weakened.
This leads to more frequent bone breakages.
My mother unexpectedly found out that she was beginning to show
signs of osteoporosis about 3 years ago in a bone scan... we had no history of this
disease in our family, and she's really not very old. She has been on medication
that is supposed to help deposit salts back into bone ever since. The medication is
not a pleasant one (you have to take it as soon as you get up every day, and then you
cannot eat, drink, or lie down for an hour afterward), but, she has been showing signs of
slow recovery. Yeah!
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