1a injury and healing p1 Flashcards
what are the 3 components of the MSK system?
bone, muscle, connective tissue
what are the 3 components of connective tissue?
tendon, ligaments and cartilage
what is a joint?
a junction between 2 or more separate bones
what are the 2 parts of the human skeleton?
axial and appendicular skeleton
what is the the axial skeleton?
forms the main part of body e.g cranium, vertebral column + rib cage
what is the appendicular skeleton?
bones which attach to axial skeleton e.g upper and lower limbs
what are the major functions of bones?
support
protection of vital organs
movement
mineral storage (calcium)
produces blood cells
what are the 2 ways that bones can develop?
Intramembranous or endochondrial ossification
which development do flat bones use?
intramembranous ossification
what are mesenchymal cells?
stem cells
which development does long bones use?
endochondral ossification
explain the process of intramembranous ossification?
1.mesenchymal cells ->osteoblasts
2.osteoblasts spread out -> ossification centrea
3.osteoblasts secrete osteiod
4.osteoid gets calcified -> stronger, trapping osteoblasts in the matrix
5. osteoblasts now called osteocytes
6. Forms trabecular matrix
7. osteoblasts present on surface form periosteum
explain the process of endochondral ossification?
- mesenchymal cells -> chondrocytes which produce cartilage
- blood vessels on edge of cartilage bring osteoblasts that deposit -> forms bony collar
- osteoclasts degrade hyaline cartilage at the centre
- This allows blood vessels to penetrate inside and deposit bone on inside -> primary ossification centre
- secondary ossification centre forms at edges of boens
- Hyaline cartilage still remains at edges of bones
what is the main aim of endochonral ossification?
for bones to grow in length and thickness
what 2 things are bones made up of?
bone + matrix
what are the 4 different types of bone cells?
- osteogenic
- osteoblasts
- Osteocytes
- Osteoclasts
what are osteogenic cells?
bone stem cells which can differentiate into anything
what are osteoblasts?
form bone
secrete osteoid
cataylses the mineralisation of osteoid
what are osteocytes?
mature bone cells
what are osteoclasts?
break bone
where can you find osteogenic cells?
in deep layers of periosteum (bone capsule)
what are the 2 layers of the periosteum?
fibrous and cellular layer
where are osteoblasts found?
in growing parts of bones
what are the 2 major components of bone matrix
organic and inorganic components
what are the organic components of bone matrix?
type 1 collagen + ground substance
what is ground substance?
proteoglycans, glycoproteins, cytokines, GFs
what is the inorganic component of the bone matrix? (2)
calcium hydroxyapatite and osteocalcium phosphate
what are the 2 major different bone types?:
immature bone
mature bone
what is immature bone?
soft bone, is the first bone that is put down, so is relatively weak. forms into mature bone when mineralised
what is mature bone?
mineralised woven bone, is much stronger than immature bone
what are the 2 main types of mature bone?
- Cortical/compact bone
- cancellous bone
what is cancellous bone?
spongy bone, honeycomb like structure
where is cortical/compact bone in this diagram?
what are the structural units called in compact/cortical bone?
osteons
what do the osteons form in compact bone?
lamellae
what is the Haversian canal?
found in bones and contains, blood vessels, nerves and lymphatics
what are lacunae?
small spaces in compact bone where cells sit
what is this?
periosteum
what is this?
outer cortex- compact bones
what is this?
medullary cavity
what is this?
nutrient artery
what is this?
articular cartilage
what region of the bone is this?
diaphysis
what region of the bone is this?
metaphysis
what region of the bone is this?
physis
what region of the bone is this?
epiphysis
what is interstitial bone growth?
when bone grows in length
what is appositional bone growth?
when bone grows in width
how does interstitial growth work?
happens at the growth plates found at the physics (edge of bone)
in epiphyseal side, cartilage continues to grow
in diaphysial side, cartilage dies and is replaced with bone
overall, increases length of bone
how does appositional bone growth work?
ridges in periosteum creates grooves which allows blood vessels to enter allowing more cells (osteoblasts) to be laid down
a lady falls over and breaks her hip. what type of fracture is this?
traumatic, low energy fracture
a guy is in a motorcycle accident and breaks his leg. what type of fracture is this?
traumatic, high energy fracture
what are the 3 mechanisms of fractures?
- trauma
- Stress
- Pathological
give some examples of pathological causes of bone fractures?
osteoporosis
cancers
vit d deficiency
OI
pagets
how can stress lead to fractures?
overuse of bones => increased stress exerted on bones =. bone weakening => stress fracture
what is the pathophysiology of osteoporosis?
osteoclast activity> osteoblast activity
what is the difference between osteoporosis and osteopenia?
osteopenia - your levels are only 1-2.5 Standard deviations form the normal range
osteoporosis - levels are >2.5
which groups of people are more likely to get osteoporosis?
women + old people
why is osteoporosis more common in women?
as oestrogen usually protects them, but post-menopause, you no longer secrete it so get weaker boens
what causes OI (osteogenesis Imperfecta)
genetic condition when you get decreased type 1 collagen
what is a key sign of certain types of OI?
blueish scleras
what is pagets disease?
when you get excessive bone breakdown, leading to excessive remodelling of bone-> deformed bones
what are blastic tumours?
make bone thicker
what are lytic tumours?
make holes in bones
what are the 4 overall steps of fracture healing and the types of cells involved?
- bleeding -blood
- inflammation - neutrophils/macropahges
- repair - blast cells e.g fibroblasts
- Remodelling - osteoclasts/blasts
Explain fracture healing?
- bone breaks
- Haematoma forms, which release cytokines
- get soft callus formation (type 2 collagen- cartilage)
- soft callus converted into hard callus = bone
- excess bone is removed
what are the 2 types of bone healing?
- primary bone healing
- secondary bone healing
how long does it take for bones to heal?
3-12 weeks
What is Wolff’s law?
Bone grows and remodels in response to the forces that are placed on i
What is primary bone healing?
- Intramembranous healing
- Mesenchymal stem cell goes straight to osteoblast and there’s direct formation of woven bone
- Happens when you have a stable fracture and ends of bone are really close together
What is secondary bone healing?
- Endochondral healing
- Results in more callus forming
- Involves responses in the periosteum and external soft tissues
- Occurs when you have a relatively stable fracture
- Mesenchymal stem cell goes to chondral precursor which produces bone cells
What are the main principles of fracture management?
- Reduction- bring fracture ends together
- Hold- the ends in the right position with metal or no metal
- Rehabilitate- once bone has healed, limb will still be weak- needs rehabilitation
What is closed reduction?
- Pulling bones back together without opening skin
- use hands to maneovoer bone pieces back into position
- used for less severe bone fractures
- Can be through traction of skin or skeletal (pins in bone)- wrapping bandage around leg/putting pin in bone and attaching weight to other end to realign bones
What is open reduction?
- Mini-incision
- Full exposure
- These are again to realign the bones
essentially, undergo a surgery to reallign bones
What are the different ways of holding a fracture?
- Fixation
- Plaster- closed
- Traction (skin or skeletal)- closed
what is traction?
basc when you use pulleys to help heal bones
what are the 2 types of traction?
- skin
- skeletal
what is bone fixation?
when you put some type of metal near bone to help hold the bone in plae
what is bone fixation?
when you put some type of metal near bone to help hold the bone in place
what are the 2 main ways of fixating a fracture?
- internally (through the bone)
- externally (on top of skin)
what are the 2 ways of internally fixating a bone?
- intramedullary (through the bone) - uses pins and nails
- extramedullary (outside bone)- uses plates, pins and screws
what type of fixation does this image show?
extramedullary internal fixation
what type of fixation does this image show?
intramedullary internal fixation
what are the 2 main types of external fixation?
- monoplanar
- mulitplanar
what is monoplanar external fixation?
the pins are connected by a single rod in a plane
what type of fixation is this?
monoplanar external fixation
what is multiplanar external fixation?
when you have pins that are connected by mutliple rods in multiple planes
what type of fixation is this?
multiplanar external fixation
what are the different aspects of rehabilitation for bone?
- Using the limb- retraining it with physiotherapy and using pain relief if necessary
- Moving it
- Strengthening it
- Weight bearing (in case of lower limb)
