bone overview/basics

Question 1

functions of bone

Answer 1

support - framework and shape of body
protection - surrounds major internal organs and vasculature
locomotion - joints allow flexibility and attachment site of muscles
haematopoesis - reservoir of stem cells forming blood cells
lipid and mineral storage - adipose tissue stored within bone marrow and calcium within hydroxyapatite crystals

Question 2

different types of bone

Answer 2

flat bones - protect organs
long bones - support and facilitate movement
irregular bones - vary in shape and structure
short bones - provide stability and some movement
sesamoid bone - embedded within tendons and protect them from stress/wear

Question 3

what is primary/woven bone?

Answer 3

first type of bone to be formed - in embryonic dev and fracture healing
consists of osteoid, randomly arranged collagen fibres
temporary structure replaced by mature lamellar bone

Question 4

what is lamellar/secondary bone

Answer 4

bone of adult skeleton
highly organised sheets of mineralised osteoid, making it stronger than woven bone
can be divided into: compact or spongy

Question 5

what is compact/cortical bone

Answer 5

found in diaphysis, forms outer part of bone
organised in concentric circles around haversian canal
haversian canal are connected by volkmanns canals which contain small vessels that also supply periosteum

Question 6

what is spongy/cancellous bone

Answer 6

found in epiphysis, irregular crosslinking of trabeculae to form porous yet strong bone resistant against multidirectional lines of force
large spaces between tabeculae give it honeycomb appearance - contains red bone marrow

Question 7

ecm provides biomechanical and structural support containing:

Answer 7

collagen - 90% type 1 and some type 5
mineral salts - calcium hydroxyapatite
calcification of bone occurs when mineral salts interpose between collagen fibres

Question 8

2 ways bone can grow:

Answer 8

endochondral: formation of bone onto temporary cartilage scaffold e.g hyaline cartilage replaced by osteoblasts secreting osteoid in femur
+ provides length
intramembranous: formation of bone directly onto fibrous connective tissue e.g temporal bone/scapula
provides width to bone

Question 9

what is osteoporosis

Answer 9

decrease in bone density, reducing structural integrity

osteoclast>osteoblast

Question 10

what is rickets/osteomalacia

Answer 10

vit d/ calcium deficiency in children

Question 11

what is osteogenesis imperfecta

Answer 11

abnormal synthesis of bone

increased fragility of bones, bone deformity and blue sclera

Question 12

what is a fracture

Answer 12

discontinuity of bone

Question 13

what is primary/ direct bone healing

Answer 13

intramembranous healing, occurs via haversian canals

slow process

Question 14

secondary/indirect healing

Answer 14

endochondral healing involves responses in periosteum and external soft tissues
fast process resulting in callus formation (fibrocartilage)

Question 15

what are the prerequisites for healing

Answer 15

minimal fracture gap
no movement if direct bony healing or some movement if indirect bone healing
patient physiological state - nutrients, growth factors, age, diabetic,smoker

Question 16

stages in fracture management

Answer 16

resuscitate - save patients life, then worry about fracture
reduce - bring bone back together in acceptable alignment
rest - hold fracture in position to prevent distortion/movement
rehabilitate - get function back and avoid stiffness

Question 17

conservative forms of fracture management

Answer 17

rest, ice,elevation
plaster/fibreglass cast or splint
traction - skin/bone

Question 18

surgical forms of fracture management

Answer 18

external fixation
open reduction and internal fixation
im nail
mua and k wire
anthroplasty:
hemiarthroplasty/ total joint replacement

Question 19

what is a non union fracture

Answer 19

broken/fractured bones does not heal in expected period of time

Question 20

what is malunion fracture

Answer 20

fracture has healed but in less than optimal position