Bones are composed of an organic matrix containing collagen and proteoglycans, as well as an inorganic component of calcium hydroxyapatite. Bones contain osteoprogenitor, osteoblast, osteocyte, and osteoclast cells. Bone formation involves the production of osteoid by osteoblasts, mineralization of osteoid, and remodeling by resorption and reformation mediated by osteoclasts and osteoblasts respectively. Bones form through endochondral ossification from cartilage or membranous/periosteal ossification from connective tissue. Common bone abnormalities include congenital defects, metabolic bone diseases such as osteoporosis, bone infections, bone tumors, and fractures.

1. Bones

2. Structure: long bone

3. Component of bone
• Organic matrix
- Type I collagen: Osteoid + proteoglycan
- Type II collagen: cartillage
• Inorganic component
eg; Ca hydroxyapatite
• Cells
- Osteoprogenitor
- Osteoblast
- Osteocytes
-Osteoclast
• Tissue: Periosteum

4. Bone formation
• Production of Osteoid
• Mineralization of osteiod
• Remodelling by resoption & reformation
Osteoblast  (Production)
Osteoid  (Mineralization)
Woven bone  (Remodelling)
Lamellar bone.

6. Ossification
• Endochondrial Ossification –frm cartillage

7. • Membranous / Periosteal Ossification – frm
connective tissue

8. Quiz: Fn of bone???

9. Involvement of:
PTH Vit D Calcitonin

10. Bone Abnormalities
1. Cogenital
2. Metabolic bone Dx
3. Inflammation
4. Malignancies
5. Trauma/ Fractures

11. 1. Congenital
• Achondroplasia
• Osteogenesis Imperfecta
• Osteopetrosis

12. 2. Metabolic Bone Dx
• Osteoporosis
• Osteomalacia, Rickets
• Paget’s Dx (of bone!!)/ Oteitis deformans
• Renal Bone Dx/ Renal osteodystrophy
• Hyperparathyroidism

13. 3. Inflammation
• Osteomyelitis
(osteon, meaning bone, myelo- meaning
marrow, and -itis meaning inflammation)

14. 4. Malignancies
Bone tumors
Primary
Bone Forming
Tumors
Cartillage
Producing
Tumors
Others
Ewing’s Sarcoma
Myeloma
Solitary
plasmacytoma
Multiple
Myeloma
Osteoclastoma
(Giant cell
tumors)
Secondary

15. Malignancies
Bone Forming
Tumors
Benign
Osteoma
Osteoid
Osteoma
Ostoeblastoma
Malignant Osteosarcoma

16. Malignancies
Cartillage
Producing
Tumors
Benign
Osteochondroma
(En)chondroma
Malignant Chondrosarcoma

17. Malignancies
• Malignant  Primary (what it produce)
 Secondary (metastasis)
*most common bone tumours in children and
young adult Primary Bone Tumours
* most common bone tumours in older adult
Myeloma and Mets from other site (brest,
prostate, lung, kidney)

18. 5. Trauma/ Fractures
• Comminuted
• Displaced
• Spiral
• Complicated
• Depressed
• Stress fracture
• Pathologic fracture (tumours, osteoporosis,
osteomalacia, Paget’s, cogenital)

19. Healing of bone
Haematoma Granulation
Procallus
formation (soft
tissue)
OssificationRemodelling