1. 6-9 Fractures
Fractures are cracks or breaks in bones that are caused by physical stress
Fractures are repaired in four steps:
Spongy bone of
internal callus
Cartilage of
external callus
Fracture
hematoma
External
callus
Spongy bone of
external callus
Dead bone
Bone fragments
Periosteum
Internal callus
External callus 1
Fracture hematoma formation:
Immediately after fracture, extensive
bleeding causes a large clot to form
(fracture hematoma). 2
Callus formation: Internal and
External calluses form, producing
an internal spongy bone network
and an external seal of cartilage
and bone. 3
Spongy bone formation:
The external seal of cartilage
is replaced by bone; struts of
spongy bone unite the broken
ends. Fragments of dead bone
have been removed. 4
Compact bone
formation. Initial
swelling subsides
with remodeling.
Almost as good
as new!

2. the types of fractures… (Be able to match a description of the type of fracture with its name, this would make a great question on the lab exam, eh?…)
Fractures are named according to their external appearance, location and the nature of the crack or the break in the bone
The broadest general categories are:
Closed (simple) fractures that are completely internal and can only be visualized by x-rays
Open (compound) fractures that project through the skin, which can complicate the condition with secondary infection
Many fractures fall into more than one category, because terms overlap…

3. Transverse fractures break a bone shaft along its long axis
ulna

4. Displaced fractures produce new and abnormal bone arrangements.
(Nondisplaced fractures retain the normal alignment)

5. Compression fractures occur in vertebrae subjected to extreme stresses
Compression fractures occur in vertebrae subjected to extreme stresses. (like falling on your backside in an abrupt “sitting” manner)

6. Spiral fractures are produced by twisting stresses that spread along the length of the bone.
tibia

7. Epiphyseal fractures tend to occur where the bone matrix is undergoing calcification and the chondrocytes are dying. Clean transverse fractures heal well (for obvious reasons) if treated properly.
femur

8. Comminuted fractures shatter the affected area into many bony fragments.
femur

9. Greenstick fractures are a partial fracture, where one side of the shaft is broken and the other side is bent. This happens frequently in children.
radius

10. Colles fractures are a break in the distal portion of the radius
Colles fractures are a break in the distal portion of the radius. (typically caused by extending your hand to cushion a fall)

11. Pott’s fractures occur at the ankle and affect both bones of the leg.
(this is a common sports injury)