Bone Pathology Flashcards
What is Osteoporosis
Osteoporosis is a health condition that weakens bones, making them fragile and more likely to break. It develops slowly over several years and is often only diagnosed when a fall or sudden impact causes a bone to break (fracture).
- DIminisehd bone mass
- Disruption of microarchitecture
- Loss of trabeculae
- diminished bone strength
- Increased suscpetibility to insufficiency fractures
Embryonology of the parts of the bones
- Bone -develops from mesoderm (mesenchyme)
- Axial skeleton - from somites
- Appendicular skeleton from lateral mesoderm
- Cranial skeleton - directly from
- Mesenchyma - membranous bones
- Rest - throigj intermediate hyalien cartilage
What is osteogenesis and ossification
- Osteogenesis = whole process of development of an bone from mesenchyme
- Ossification = selective process of hardenign or radiological/histiological evidence of bone formation from membrane or crtilage
- Membranous ossification, Endochondral ossification, Osteogensis imperfecta.
What are the Classifications of bones:
- Anatomical - long, flat
- Structural:
- Macroscopic - cortical/comapct and cancellous/spongy
- Hisitiological - lamellar and woven
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/671/779/a_image_thumb.png?1644577781)
Bone histology:
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/671/833/a_image_thumb.png?1644577811)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/671/915/q_image_thumb.png?1644577944)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/671/915/a_image_thumb.png?1644577952)
Decsribe Woven Bone
- Not an orderly paralll array
- Intersecting, crisscross and woven arrangement
- Iregular thick and thin bundles
- Seen in foetus
- Recapitulated in fracture healing
Describe the Parts of a long bone
- Diaphysis - shaft (primary centre of ossification)
- Metaphysis - below the growht plate
- Epiphysis - upon/above the growht plate (secondary centre of ossification)
- Physis - growth (plate)
- Nutrient artery = through nutrient foramen - directed away from growing end- ‘to elbow i go, from the knee i flee- Milekrs position)
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![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/672/017/a_image_thumb.png?1644578196)
Where does provisional calcification start in the growth plate?
- Upper and lower hypertrophic zone
- Provisional calcification starts in latter which is storngest layer of growth plate compared to upper hyp zone which is the weakest and usually involved in growth plate injuries
- Zone of endochondral ossification - intense calcification and in continuity with metaphysis 4
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/672/222/a_image_thumb.png?1644578318)
What are the ones labelled G,H,O,R
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/672/700/q_image_thumb.png?1644578342)
G = Growth zone
H= hypertorphic zone
0 = ossification zone
R= Remodelling zone
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/672/700/a_image_thumb.png?1644578387)
What are labelled
![](https://s3.amazonaws.com/brainscape-prod/system/cm/372/672/727/q_image_thumb.png?1644578403)
Osteoid and osteoclasts
What is the sequence of longitudinal growth in long bone
- By provisional calcification of cartilage - endochondral ossification:
- Proliferation - increase in number by mitoses/cell division
- Hypertrophy - increase in size
- Maturation
- Degeneration
- Calcification
Describe Diametric Growth in long bones
- Miantained by periphysis
- Ring of La Croix- Surroundig epiphysis
- Zone of Ranvier - surroundign metaphysis.
What factors affect bone growth?
- Mechanical/Local - s-ace - epiphysiodesis and epiphyseal distarction
- Distractio osteosynthesis - Ilizarov
- Systemic- Endocrine, Paracrine, autocrine
- PTH-rP (parathyroid hormone related protein)
- Indian hedgehog Ihh proetin
Membranous ossification - Describe the main steps
- (Omit cartilage step)
- Primtiive emsenchyme -> osteoprogenitor cells 0> osteoblasts
- Lay down specialised collageb - osteoid
- Calcify
- Intramembranous ossification is the direct deposition of bone on thin layers ofconnective tissue and is characteristic of the bones on the top of the skull.