Injury+Healing Flashcards
What are bones made of?(2)
Cells and matrix
What is the organic component of bone matrix made up out of?
What is the inorganic component of bone matrix made up out of?
Purpose of osteogenic cells?
Bone stem cell
Purpose of osteoblasts?
Producing bone
-Secretes osteoid
-Catalyses mineralisation of osteoid
Purpose of osteoclasts?
Destroying bone
-Dissolve+reabsorb bone via phagocytosis
-Derived from bone marrow
Purpose of osteocytes?
‘Mature’ bone cell
-Formed when an osteoblast becomes imbedded in its secretions
-Sense mechanical strain to direct osteoclast and osteoblast activity
What type of ossification produces long bones?
Endochondral
Mesenchymal>Cartilage>Bone
What type of ossification produces flat bones?
Intramembranous
Mesenchymal>bone
What is involved in endochondral ossification?
- Bone collar formation
- Cavitation
- Periosteal bud invasion
- Diaphysis elongation
- Epiphyseal elongation
What is involved in intramembranous ossification?
- Condensation of mesenchymal cells which differentiate into osteoblasts that secrete matrix (osteoid)
- Secreted osteoid traps osteoblasts which become osteocytes. A bunch of these together form an ossification center
- Multiple ossification centers form and fuse. Trabecular matrix and periosteum form
- Compact bone develops superficial to cancellous bone. Crowded blood vessels bring in mesenchymal cells and form red marrow
What are the primary and secondary ossification centers in endochondral ossification?
Primary-Diaphysis
Secondary-Epiphysis
What key feature in mature bone is not present in immature bone?
Lamellar (layer) structure – relatively strong
Which type of ossification is faster?
Intramembranous
Where are bone trabeculae found?
Cancellous bone
What are the differences in the 2 types of mature bone?
Cancellous bone-
‘Spongy’ – honeycomb structure
Not suitable for weight baring
Cortical bone-
‘Compact’ – dense
Suitable for weight baring
What is haversians canal?
A passageway containing blood vessels, nerves and lymphatics in the center of an osteon
What are the 2 layers in the periosteum?
Inner osteogenic layer
Outer fibrous layer
What are bone osteons?
Circular structures in cortical bone with repeating lamellae
What are volkmans canals?
Transverse perforating canals
What are bone lacunae
Small spaces containing osteocytes
Tiny Canaliculi radiate from lacunae filled with extracellular fluid.
What does the medullary cavity contain?
Yellow bone marrow
Where is articular cartilage found?
On surface of bone at joint only
Where do you find osteogenic cells?
Marrow + Deep layers of periosteum
Where do you find osteoblasts?
Growing portions of bone incl. periosteum and endosteum
Where do you find osteoclasts?
Bone surfaces and sites of old, injured or unneeded bone
Where do you find osteocytes?
Entrapped in matrix
What are the 2 different types of growth where bones increase in length and thickness
Interstitial-Length
Appositional-Thickness
How and where does interstitial growth occur?
Happens at the physis (physeal plate)
Zone of elongation in long bone
Contains hyaline cartilage
Epiphyseal side – hyaline cartilage active and dividing to form hyaline cartilage matrix
Diaphyseal side – Cartilage calcifies and dies and then replaced by bone
What occurs when calcium is above normal to regulate it?
What occurs when calcium is below normal to regulate it?
What is the pathway to a stress fracture?
What are the mechanisms of bone fracture/break?
What are the pathways to pathological/insufficiency bone fractures 6,4?
What causes osteopenia/osteoporosis and describe its epidemiology?
Osteoclast activity > Osteoblast activity
>Disrupted microarchitecture
Female > Male 4:1
Postmenopausal Osteoporosis – Women 50-70
Senile Osteoporosis - > 70
Secondary osteoporosis: Any age, 60% Male
Hypogonadism
Glucocorticoid excess
Alcoholism
Associated with ‘fragility fractures’ – hip, spine, wrist
Low energy trauma fracture
Describe the epidemiology of Vit D deficiency
Vitamin D facilitates calcium, magnesium and phosphate absorption
Dietary or synthesized from the sun
Inadequate Calcium or Phosphate Defect in osteoid matrix mineralization
Paeds – Rickets
Adults - Osteomalacia
What causes pagets disease and what are the 4 stages?
Genetic & Acquired factors
Excessive bone break down and disorganized remodeling deformity, pain, fracture or arthritis
May transform into a malignant disease
4 stages:
Osteoclastic Activity
Mixed osteoclastic-osteoblastic activity
Osteoblastic activity
Malignant degeneration
What causes congenital osteogenesis imperfecta?
‘Brittle Bone Disease’
Hereditary – autosomal dominant or recessive
Decreased Type I Collagen due to:
Decreased secretion
Production of abnormal collagen
Insufficient osteoid production
Effects:
Bones
Hearing
Heart
Sight
What are the 4 primary bone cancers?
What are the 4 major stages of bone healing and what subtances/cells are required for each?
What types of cancers are bone forming(blastic) and bone breaking(lytic)?
What are the 3 stages of fracture healing?
Which image is more likely primary and secondary bone healing?
Primary-Left
Secondary-Right
-Secondary bone healing produces more callus
What is the pathway for fracture management?
What are the methods of fixation and their groups?
What is the pathway for rehabilitating a broken bone?(4+2)
How do you grade tendon/ligament injury?
Grade I – Slight incomplete tear – no notable joint instability
Grade II – Moderate / Severe Incomplete Tear – Some joint instability. One ligament may be completely torn
Grade III – complete tearing of 1 or more ligaments – Obvious instability. Surgery may be required
What are the 2 long term ACL rupture treatment pathways?
What do you need to consider in an ACL tear patient?
Functional Demands
Patient factors
Compliance
