Osteocytes
mature bone cells
Osteoblasts
cells that rebuild bone
osteoclasts
cells that tear down bone
Wolff's law
Bones grow or remodel due to mechanical stress
1.Handedness causes increased bone thickness
2.Curved bones are thickest where most likely to buckle
3.Spongy bones remodel quickly among lines of stress
4.Projections occur where active muscles attach
Classification of Fractures
1. 1.Position bone ends after fracture
2. Completeness of the break
3. Orientation relative to long axis
4. Penetration of the skin
5. Nature of the break
Position bone ends after fracture
-Non Displaced - retain normal position
-Displaced - out of alignment
Completeness of the break
-Complete - broken through
-Incomplete - partially broken
Orientation relative to long axis
-Linear - broken parallel to long axis
-Transverse - broken perpendicular to long axis
Penetration of the skin
-Open (Compound)
-Closed (Simple)
Nature of the break
-comminuted
-compression
-depressed
-epiphyseal
-greenstick
-spiral
comminuted
bone fragments into 3 or more pieces; common in the elderly
compression
bone is crushed; common in porous bones
depressed
broken bone portion is pressed inward, typical of skull fracture
epiphyseal
epiphyseal plate tears, seperating epiphysis from diaphysis
greenstick
bone breaks incompletely, much in the way a green twig breaks. one side of the shaft splits, the other side bends
spiral
ragged break occurs when excessive twisting forces are applied to a bone
long break
hyaline cartilage
Most common type of cartilage; it is found on the ends of long bones, ribs, and nose
elastic cartilage
cartilage with abundant elastic fibers; more flexible than hyaline cartilage
-external ear
Fibrocartilage
Pads between vertebrae that are shock absorbers