classes of northwest institute of health sciences of 2nd batch, 1st semister

1. BONE-I
DR. SADAF AZIZ
LECTURER, NORTHWEST COLLEGE OF PHYSICAL THERAPY

2. TODAY’S LECTURE
 Bone
 Classification of bone
 Parts of developing long bone
 Gross structure of bone
 Development of bone

3. WHAT IS BONE?
 One-third organic connective tissue. Makes it tough & resilient. Afford
resistance to tensile forces.
 Two-third inorganic calcium salts. Makes it hard & rigid. Afford resistance
to compressive forces of weight- bearing and impact forces of jumping.
 Living tissue & highly vascular.
 Greater regenerative power.
 Mould itself to changes in stress.
 Shows disuse atrophy & overuse hypertrophy

5. GROSS STRUCTURE OF AN ADULT
LONG BONE
 SHAFT
 Perisoteum
 Cortex
 Medullary cavity

7. THE TWO ENDS
 Cancellous bone covered with hyaline cartilage

8. PARTS OF A YOUNG BONE
Primary center & secondary center
1. Epiphysis
2. Diaphysis
3. Metaphysis
4. Epiphysial plate of cartilage

9. 1. EPIPHYSIS
The ends & tips of bone which ossify from secondary centres
 Pressure epiphysis
 Traction epiphysis
 Atavistic epiphysis
 Aberrant epiphysis

11. 2. DIAPHYSIS
 Elongated shaft of bone which ossify from a primary center

12. 3. METAPHYSIS
 The epiphyseal end of a diaphysis
 Zone of active growth, hair-pin bends
 Common site of osteomyelitis in children
 after the epiphyseal fusion vascular communications establish between
metaphysical and epiphyseal arteries.

13. 4. EPIPHYSEAL PLATE OF CARTILAGE
 Separates epiphysis from metaphysis
 Lengthwise growth of a long bone
 After epiphyseal fusion, the bone can no longer grow in length

14. DEVELOPMENT & OSSIFICATION OF
BONES
 Bones first laid down as mesodermal (connective tissue) condensations
 Conversion of mesoderm into bone is Intramembranous/ mesenchymal
ossification. The bones are called Membrane (dermal) bones
 Conversion of cartilaginous model into bone is called Intracartilaginous /
endochondral ossification. The bones are called Cartilaginous bones
 Ossification takes place by centers of ossification
 Primary centers forms diaphysis
 Secondary centers form epiphysis
 Fusion of epiphysis with diaphysis starts at puberty and complete by age of 25
years
 Law of ossification
 Growing end of bone

16. GROWTH OF BONE

17. CLASSIFICATION OF BONES
A. According to shape
B. Developmental classification
C. Regional classification
D. Structural classification

18. A. ACCORDING TO SHAPE

19. 1. LONG BONES
 Diaphysis & epiphysis.
 Shaft separated by 3 borders.
 Nutrient foramen
EXAMPLES:
 Typical long bone, humerus, radius , ulna
 Miniature long bone, metacarpals, metatarsals, phalanges
 Modified long bone, clavicle

21. 2. SHORT BONES
 Shape is cuboid, cuneiform, trapezoid , scaphoid.
EXAMPLE:
 Tarsal & carpal bones

22. 3. FLAT BONES
 Resemble shallow plates and form boundaries of body cavities
EXAMPLE:
 Bones in the vault of skull, ribs, sternum and scapula

24. 4. IRREGULAR BONE
 Vertebrae, hip bone, bone in the base of skull

25. 5. PNEUMATIC BONES
 Irregular bones containing large air spaces lined by epithelium
EXAMPLES:
 Maxilla, sphenoid, ethmoid

26. 6. SESAMOID BONES
 Bony nodules found embedded in tendons or joint capsules.
 No periosteum, ossify after birth.
 Surface of contact are covered with hyaline cartilage and lubricated by
bursa or synovial membrane
EXAMPLES:
 Patella, pisiform, fabella etc

28. 7. ACCESSORY BONES
 Not always present .
 May occur as un-united epiphysis developed from extra centres of
ossification
EXAMPLES:
 Sutural, lateral tubercle, tuberosity of 5th metatarsal

30. 8. HETEROTROPIC BONES
 Bones sometimes develop in soft tissues
 Rider’s horse

31. B. DEVELOPMENTAL CLASSIFICATION

32. 1. MEMBRANE BONES
 Ossify in membrane
 Intramembranous or mesenchymal ossification
 Derived from mesenchymal condensations
EXAMPLES:
 bones of vault of skull and facial bones

35. 2. CARTILAGINOUS BONES
 Ossify in cartilage
 Intra-cartilaginous or endochondral ossification
 Derived from preformed cartilaginous models
EXAMPLES
 Bones of limbs, vertebral column, thoracic age

37. 3. MEMBRANO-CARTILAGINOUS
BONES
 Ossify partly in bones and partly in cartilage
 EXAMPLE
 Clavicle, mandible, occipital, temporal , sphenoid

38. 4. SOMATIC BONES
 Most of the bones are somatic

39. 5. VISCERAL BONES
 Develop from pharyngeal arches
EXAMPLES
 Hyoid bones, part of mandible, ear ossicles

40. C. REGIONAL CLASSIFICATION
 Axial skeleton
 Appendicular skeleton

41. D. STRUCTURAL CLASSIFICATION
Macroscopically
 Compact bone
 Cancellous/ spongy bone
 Wolf’s Law
 Pressure Lamellae
 Tension lamellae

44. WOLFF’S LAW

45. PRESSURE & TENSION LAMELLAE

46. Microscopically;
 Lamellar bone
 Woven bone
 Fibrous bone
 Dentine
 Cement

47. LAMELLAR BONE

48. WOVEN BONE

49. DENTINE & CEMENT

50. BLOOD SUPPLY OF BONE

51. SELF STUDY….
 Functions of bone
 Growth of a long bone

52. THE END…!!