General Anatomy of bones and cartilage ppt

GA of bones and cartilage

1. Dr Mahwash Azam Khan
Bones and Cartilages

2. Learning Objectives
•Skeletal system
•Bone and bonemarking
•Classification of bones
•Ossification of bones
•Bones remodelling
•Blood supply

3. Skeletal system
Human skeletal system is composed of bones and associated
ligaments, tendons and cartilages.
Bilaterally symmetrical with typical vertebrate pattern.

4. Axial Skeleton
•Bones present in axial
region forming long axis
of body.
•80 in number.
•involved in protection,
support etc.
•include skull, vertebral
column, ribs etc

5. Appendicular Skeleton
•Bones of upper and
lower limbs
•126 in number
•Involved in locomotion

6. Bone
It is a highly vascular, living and constantly ch
anging mineralized connective tissue.
It is remarkable for its hardness,
resilience and regenerative capacity
as well as its characteristic growth
mechanism.

7. Function of bones
Mechanical Functions:
•shape and support of the body
•act as a protective barrier to external forces
•as a lever of locomotion
•reduce weight, produce resonance to voice (pnuematic
bones)
•Physiological Functions:
•storage and metabolism
•hematopoietic function

8. Composition of bone
All the bones are made up of or
ganic (connective tissue) and in
organic (minerals)part so they
can be studied after either
maceration
or decalcification

9. Maceration
•Process by which all
structures attached to
bones and organic material
including bone marrow are
removed.
•Bones are hard, clean and
dry, prone to fracture, loose
their elasticity

10. Decalcification
•Process by which all
inorganic material of
bone is removed.
•Bones are soft, highly
flexible and easily be
deformed into any
shape.
bone:
•. Has been demineralized
• Has had its inorganic component removed

11. Classification of bones

12. 1.Developmental Classification
2.Regional Classification
3.According to Size and Shape
4.According to Evolution

13. i.Membranous Bones:
Develop directly from condensation of mesenchyme
through intramembranous ossification.
mesenchyme> osteoblasts>osteoid>mineralization> bone
Examples:
Clavicle, bones of cranial vault and bones of face(maxilla,
frontal, parietal)
1. Developmental Classification

14. Membranous Ossification:

15. ii. Cartilaginous Bones:
Bony tissue formed through intracartilaginous ossificatio
n
hyaline cartilage> bone tissue
Examples:
Bones of face, sphenoid and all limb bones
except Clavicle

16. Endochondral ossification
Stages 1-3 during fetal week 9 through 9
th
month
Stage 4 is just
before birth
Stage 5 is process of
long bone growth
during childhood &
adolescence

17. iii.MembranoCartilaginous Bones :
Partly develop in membranes and partly in Cartilaginous
Model
Examples:
Temporal and Mandible

18. 2. Regional Classification:
i.Axial Bones
ii.Appendicular Bones

19. 3. Classification based upon bone
shape

20. Classification based upon bone
shape
1.Long Bones
2.Short Bones
3.Flat Bones
4.Irregular Bones
5.Sesamoid Bones
6.Accesory Bones

21. 1. LONG BONES:
•Cylindrical shaft and
two expanded ends
which are smooth and
articular
Classification is based
on shape not size
Example: clavicle, tibia,
femur, humerus

23. GROSS ANATOMY OF LONG BONES
PARTS OF BONE:
–Diaphysis (shaft)
–Bone Ends
–Epiphysis
–Metaphysis
–Articular Cartilage
–Medullary Cavity

24. TYPES OF BONE TISSUE:
COMPACTBONE:
•Densely and regularly
packed trabeculae with little
intertrabecular spaces.
•Bear stress and strain
hence provides strength
•Hard
•Opaque appearance
•Yellow Marrow
•Shaft of long bones like
humerus and femur

25. SPONGY BONE
•Trabeculae loosely and
irregularly packed with
more intertrabecular
spaces.
•Bear compression
forces at joints
•Present in ends of long
bones
•Red Marrow

26. Layers around the bone:
PERIOSTEUM:
–Covers all bones except parts
enclosed in joint capsules
–It is made up of:
–an outer, fibrous layer
–and an inner, cellular layer
–Functions:
– Isolate bone from surrounding
tissues
– Provide a route for circulatory
and nervous supply
– Participate in bone growth and
repair

28. ENDOSTEUM:
•An incompletecellular layer:
•lines the marrow cavity
•covers trabeculae of spongy bone
•Contains osteoblasts,
osteoprogenitor cells and
osteoclasts
•Is active in bone growth and
repair

29. 1a. MINIATURE LONG BONES
•Type of long bones, having
short length
•Metacarpals and phalanges
of hands
•Metatarsals and phalanges
of foot

30. 2. SHORT BONES
•Same dimension in length,
width and thickness but
have irregular shape
•Smaller and non tubular
•Carpal and Tarsal bones

31. 3.FLAT BONES
•Thin and curved
•Broad surfaces for muscle
attachments
•Ribs, sternum, scapulae,
bones of cranial vault

32. 4. IRREGULAR BONES
•Bones consist of thin layers of
compact bones over spongy
bone
•No shaft, epiphysis or diaphysis
•Hip bones, vertebrae, bones of
face

33. PNEUMATIC BONES:
•Some bones of skull
contain air filled
cavities called air
sinuses
•maxilla, ethmoid and
mastoid bones

34. 5. SESAMOID BONES
•Bony nodules which lie
embedded within certain
tendons
•Patella, Pisiform

35. 6.ACCESSORY BONES
These bones are not
always present
•Cervical rib,
polydactyly,
polymyelia,
•wormian bones.
•riders bones

36. 4. Classification based on
Evolution:
1. EXOSKELTON/DERMAL
»Present in outer aspect, have protective role, not covered by
muscles
»e.g skull, clavicle, dentine
2. ENDOSKELETON/DEEP
»Covered by muscles
»e.g All other bones

37. Bone Remodelling
•Bones remodelling occurs in two phases:
–Osteoclasts remove old bone by releasing
acids and enzymes
–Osteoblasts deposit new tissue by secreting
osteoid thus allowing for mineral deposit, and
eventually new bone growth

38. •Epiphysis first to appear is the last
to fuse and vice versa (except
fibula)
•Nutrient canal is directed away
from the growing end except fibula

39. Bone Deposition
•Thin band of osteoid (unmineralized bone) l
aid down by osteoblasts, located on inner su
rface of periosteum and endosteum.
•Mineral salts (Ca2+ and Pi) are precipitated
out of blood plasma and deposited amongst
the osteoid fibers
–Requires proper Ca2+ and Phosphate ion con
centration
–Vitamin D, C, A, and protein from diet
•(Poor nutrition will negatively affect bone he
alth)

40. •During early years (age 0 –35) remodelling is most
active bone deposition heavily outweighs bone
resorption
•Remodelling declines by around age 35 and by
around age 40, the process reverses (resorption
outpaces deposit)
•Resultloss of 5 to 10% of bone mass each decad
e after age 40
Bone Remodelling

41. Bone resoprtion will outpace bone deposit,
but ensuring you have strong, healthy bones
when you are younger will keep your bones
healthier as you age
BoneRemodelling

42. Growing end hypothesis
•Applicable only on immature long bones.
•Growth of bone is dependent upon growth
cartilage.
•Growth cartilages two in number but
growthoccursunequallyattwoends.
•Growth is relatively more active at one
end (growing end).
•The growth plate fuses later at the fast
growing end.

43. BONE MARKINGS

44. 1.Smooth articular surfaces:
Head
Capitulum
Facet
Condyle
Trochlea
Fossa

45. •Head
Large, rounded
articular surface
Set apart from the
other bone
Head of femur

46. •Capitulum
small rounded
articular eminence
•Trochlea
Pulley shaped
articular surface

47. •Condyle
rounded
protuberance at
the end of bone
•Fossa
hollow depressed
region of a bone

48. •Facet
Small smooth flat
articular surface

49. Cont….
2.Irregular depressions on non articular
areas:
Groove/ Sulcus
Notch/ Incisura
Hiatus
Fovea/ Pit

50. •Groove / sulcus:
Serve as passage for
nerves

51. •Notch/ Incisura
Depression bridged
by a ligament

52. •Hiatus
Gap on the surface of
the bone

53. •Fovea
Small and shallow depression
on the surface of the bone

54. 3.Hole /Aperture:
Foramen
Canal
Fissure
Meatus

55. •Foramen
A shallow hole in the
bone

56. •Canal
A deep and lengthy hole
in the bone

57. •Fissure
A cleft in or between
the bones

58. •Meatus
A canal that enters
a structure but does
not pass through it

59. Cont…
4.Projection on non articular areas:
Process
Spine
Ramus
Hamulus/Cornu/horn
Tuberosity/Trochanter/Tubercle
Crest/Line/Ridge
Lips
Epicondyle
Malleolus

60. •Processes
Large and sharply raised
area

61. •Spine
Small, sharp and pointed
raised area

62. •Ramus
It is a broad arm of a
process projecting
from the main body
of the bone

63. •Horns/Cornu/Hamulus
Small sharp and curved
process

64. •Trochanter/ tuberosity
Rounded or irregular raised
area on the surface of the
bone

65. •Crest/ Line/ Ridge
Elongated elevation
like a line

66. •Epicondyle
Projection close to a
condyle

67. •Malleolus
A hammer head like
rounded projection

68. Blood Supply Of Bones
Blood Supply Of Long Bones:
1.Nutrient artery
2.Periosteal arteries
3.Epiphyseal arteries
4.Metaphyseal arteries

69. BLOOD SUPPLY
Figure 6–12

70. VEINS:
-periosteal & nutrient veins
-chief veins escape through foramina at ends of bones
LYMPH VESSELS :
-exists in periosteum
NERVES:
-sensory nerves are plentiful in periosteum
-accompany the nutrient artery

71. VASCULAR SUPPLY OF BONES

72. CARTILAGE

73. CARTILAGE: It is a connective tissue composed
of cells (chondrocytes) and fibres (collagen) in
matrix, rich in mucopolysaccarides.
Functions:
•Capable of withstanding stress
•acts as shock absorber

74. General features
•Has no blood vessels or lymphatics
•Nutrition is by diffusion through matrix
•No nerves –insensitive
•Surrounded by a fibrous membrane –
perichondrium
•Articular cartilage has no perichondrium –
regeneration after injury inadequate
•When calcifies –chondrocytes die –replaced by b
one

75. TYPES:
•HYALINE CARTILAGE
•FIBROCARTILAGE
•ELASTIC CARTILAGE

76. HYALINE CARTILAGE
(G. hyalos -glassy)
•Bluish white and transparent due to very fine
collagen fibres
•Abundantly distributed –tendency to calcify
after 40yrs of age
•All cartilage bones are preformed in hyaline
cartilage
•Ex –articular cartilage, costal cartilage

78. FIBROCARTILAGE
•White and opaque due to abundance of dense
collagen fibres
•Whenever fibrous tissue is subjected to great
pressure –replaced by fibrocartilage
•Tough, strong and resilient
•Ex –intervertebral disc, intraarticular disc

80. ELASTIC CARTILAGE
•Made of numerous cells and
•Rich network of yellow elastic fibres pervading
the matrix –so that it is more pliable
•Ex -Cartilage in the external ear, auditory tube